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Learn how to use mathematical operators in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python 4b - Mathematical Operators Modulo Division The modulo operator - the percentage symbol % - will work out the remainder left over when one value is divided by another. print (30 % 6) = 0 30 ÷ 6 = 5, which is a whole number, so there is no remainder and 0 is output . print (30 % 7) = 2 30 ÷ 7 = 4 remainder 2 ; so the remainder is output . You can use modulo with variables too: num1 = 33 num2 = 4 print ( "The remainder is" , num1 % num2) The remainder is 1 = A common use of modulo is to check if a number is odd or even . If a number has no remainder when divided by 2 then it is even . = num = int ( input ( "Enter a number: " )) if num % 2 == 0: print (num, "is even." ) else : print (num , "is odd." ) Enter a number: 400 400 is even. Enter a number: 191 191 is odd. = Modulo Div i sion Task 1 ( Remainder) Ask the user to input a whole number . Use the modulo operator ( % ) to check if there is a remainder when the user's number is divided by 5 . Print the re mainder. Example solution: Enter a number: 123 The remainder when divided by 5 is 3 Modulo Div i sion Task 2 ( Rollercoaster) Use the odd/even program above to help solve this problem: A rollercoaster only lets people on in groups of 4 . Ask the user to input a number for how many people are in their group. Check if that number is directly divisible by 4 using modulo division ( % ). If it is then print “Perfect groups of four!” Else print “You will be split up” . Example solutions: Welcome to the Hyper Coaster! How many in your group? 6 You will be split up! Welcome to the Hyper Coaster! How many in your group? 12 Perfect groups of four! Integer Division Integer division removes any decimal numbers when performing division , leaving just the integer (whole number ). In Python integer division is performed using // . print (20 / 3) print (20 // 3) = 6.666666666666667 6 Integer Div i sion Task 1 ( Integer Division by 5 ) Use an input line with int to ask the user to enter a number . Use integer division ( // ) to divide the number by 5 without keeping any decimal values . Challenge: Improve your solution by altering the print line to be more user friendly . Example solutions: Enter a number: 27 5 Enter a number: 27 5 goes into 27 5 times. Integer Div i sion Task 2 ( Plane Rows) A large plane has 6 seats in each row. Input the number of passengers on the plane and use integer division to work out how many full rows will be filled. Example solution: How many passengers are there in total? 174 There will be 29 full rows on the plane. Exponent (Powers) An exponent is the number of times a value is multiplied by itself , for example 2 = 2 x 2 x 2 = 8 . The symbol to represent an exponent in Python is ** . For example: 4**2 represents 4 which is also 4 x 4 . 3 2 print (4**4) = 256 base = 5 exponent = 4 print (base**exponent) 625 = Exponent Task 1 ( Square Number) Use an input line with int to ask the user to enter a number . Output the square of this number. Example solution: Enter a number: 12 12 squared is 144 Exponent Task 2 ( Custom Exponent) Use an input line with int to ask the user to enter a number, this will be the base . Make another input line with int to ask for the exponent . Use ** between the base and the exponent and print it. Challenge: Make your solution better by including the base and exponent in the print line. Example solutions: Enter the base: 7 Enter the exponent: 3 343 Enter the base: 7 Enter the exponent: 3 7 to the power of 3 is 343 ⬅ 4a - If Statements 4 c - Log ical Operators ➡

Learn how to use App Inventor 2 to create simple programs. Try to complete tasks 4, 5 and 6 on this page. Perfect for Key Stage 3 students to experiment with block coding, objects and properties. App Inventor Tasks 4, 5 & 6 - Using Variables This page will teach you how to make three simple apps that use variables . These apps will prepare you for the final program - the Pop-up Blob game. App #4 - Button Masher The first app to make is a simple program that counts how many times a button is pressed (but don't press it too much! ) This app will introduce you to using variables in App Inventor. Open App Inventor 2 (use the button below) and create a new project. You will need to log in with a Google account. App Inventor 2 Firstly, grab a button and two labels and place them in the Viewer . Using the Properties tab, you need to make the following changes: Button Text to 'Press Me!' Button Height to 60 pixels and Width to 'Fill parent...' Label 1 Text to 'Number of Presses' Label 2 Text to '0' Both Label 1 and Label 2 Width to 'Fill parent...' Both Label 1 and Label 2 TextAlignment to 'centre : 1' In the Components tab change the component names to be easier to code later. Switch to Blocks layout and drag an initialize global to block into the centre. In the blank space type 'Presses' - this is the name of the variable that will store how many times the button has been pressed. Drag a 0 block from Math. This will set the number of presses to 0 when the app starts. Drag a when ButtonPresses Clicked from the ButtonPresses section and add the necessary code inside. This code increases the variable value of Presses by 1 every time the button is clicked. It also changes the LabelPresses text to display the number of presses. Improve Your App As you will have seen in the video at the top, I programmed the app to go a bit crazy when 35 presses were recorded. In the code below I have shown how to use an if then block to check if the number of presses is 35. If it is then I have made the button invisible - this is an important feature we will use in later programs. Copy this code and add the following features to the then part of the if statement: Set the background colour to black. Change the Label1 Text Colour to white. Change the Label1 Text Size to 40. Change the Label1 Text to 'You broke it...' Program 4 Complete! App #5 - Timer The second app to make is a timer that counts up one second at a time. It also needs a reset button that sets the timer back to 0 again. It will introduce you to the clock component and enabling / disabling components. Open App Inventor 2 (use the button below) and create a new project. You will need to log in with a Google account. App Inventor 2 The code for this program is straightforward; it will take more effort getting the layout right. In the Palette tab, drag a HorizontalArrangement from the Layout section. It will look like an empty grey box at first. Grab a Button as well and place it underneath. Now drag two labels into the grey box and place the second one directly after the first, it may take a few attempts to get them to appear side by side like below: The last component to drag over is Clock (it is in the Sensors section in the Palette tab). It will go into its own section underneath: Change the name of some of the components so that they make more sense. Now to make some changes in the Properties tab. You should know enough by now to work out how to change your components so that it looks like this in your Viewer : Change your layout to Blocks and add the code blocks to the right. This code makes the Label named Seconds update by 1 every second, just like a timer. The code to the left will make the Label named Seconds reset to 0 when the button is pressed. Improve Your App As you will have seen in the video at the top of this task, I added a pause/unpause button that will set the enabled feature of the timer to true or false. You will need to complete the following steps (I've been deliberately vague to make it a challenge - break it down into small steps and use the colours to help you): Add a new button. Add code that, when the new button is clicked , checks if the TimerEnabled is true . If it is, then change TimerEnabled to false . Else change it to true . Now you also need to change the Text of the Button to read either "Pause" or "Unpause" . Program 5 Complete! App #6 - Windy Day The third app to make is an app that blows leaves around your screen. It will introduce you to random numbers, the canvas and coordinates . Open App Inventor 2 (use the button below) and create a new project. You will need to log in with a Google account. App Inventor 2 In the Palette tab, drag a Canvas from the Drawing and Animation section. A Canvas allows sprites (objects) to move around inside of it. In Properties , change the Height and Width of Canvas to 'Fill parent...' for both, so it fills the whole screen. In the Palette tab, drag over five ImageSprites from the Drawing and Animation section and drop them anywhere inside the canvas. Download the leaf picture with all App Inventor images on the basics page here . Upload the leaf image it in the Media tab. In the Components tab change the names of your ImageSprites to be leaf1, leaf 2 etc. For each leaf sprite, in the Properties tab, change the Picture to the leaf you just uploaded and change Height and Width to 30 pixels each. Finally, in the Palette tab, in the Sensors section, drag over a Clock . Your Viewer should look like the image to the left. X axis Y axis 0 300 500 Now for an explanation of coordinates. Each sprite (leaf) has an x coordinate (horizontal) and a y coordinate (vertical). For example, the leaf in the top right would have coordinates of x = 270 and y = 100. Can you work out approximately what the other leaves coordinates would be? What the code blocks below do is randomise the x and y coordinates for leaf1 every second. The word integer means a whole number . Use this code and add to it to make all 5 leaves randomly change coordinates. Improve Your App Add a pause / unpause button, just like in the Timer app that pauses the timer so that the leaves stop blowing (and starts them blowing around again too). Find a nice picture (maybe of a park?) online and upload it in the Media tab. Set this as the Canvas BackgroundImage . Add an audio file of some whooshing (why not record it yourself?). Program 6 Complete! Task 7 KS3 Home

Learn about common prevention methods of minimising cyber security risks including anti0malware, firewalls and penetration testing. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 4.2: Preventing Vulnerabilities Exam Board: OCR Specification: J277 Watch on YouTube : Preventing Vulnerabilities Penetration Tests Penetration tests are carried out as part of ethical hacking. The purpose of a penetration test is to review the system's security to find any risks or weaknesses and to fix them . Internal tests are to see how much damage could be done by somebody within the company with a registered account. External tests are for white hat hackers to try and infiltrate a system from outside the company . Anti-Malware Software Anti-malware software is used to locate and delete malware, like viruses, on a computer system. The software scans each file on the computer and compares it against a database of known malware . Files with similar features to malware in the database are identified and deleted . There are thousands of known malware, but new forms are created each day by attackers, so anti-malware software must be regularly updated to keep systems secure. Other roles of anti-malware software: Checking all incoming and outgoing emails and their attachments . Checking files as they are downloaded . Scanning the hard drive for viruses and deleting them . Firewall A firewall manages incoming and outgoing network traffic . Each data packet is processed to check whether it should be given access to the network by examining the source and destination address . Unexpected data packets will be filtered out and not accepted to the network. Other roles of a firewall include: Blocking access to insecure / malicious web sites . Blocking certain programs from accessing the internet . Blocking unexpected / unauthorised downloads . Preventing specific users on a network accessing certain files . Secure Passwords ******** Usernames must be matched with a secure password to minimise the chances of unauthorised users accessing a system. Passwords should contain a mix of uppercase and lowercase letters , punctuation and numbers . Passwords should be of a substantial length (at least 8 characters) and should be regularly changed . User Access Levels Access levels are used to only allow certain users to access and edit particular files. ' Read-Only ' access is when a user can only view a file and is not allowed to change any data . For example, a teacher might set homework instructions as read-only for students to view. ' Read and Write ' access allows a user to read and edit the data in a file. For example, a teacher might set an online workbook as read and write access for students to fill in. It is important to set access levels so that only authorised users can view and change data. The more users who have access to a file, the more likely it is to be compromised. Certain users may also have no access to a file - when they can't view or edit it. Encryption Encryption is the process of scrambling data into an unreadable format so that attackers cannot understand it if intercepted during transmission. The original data (known as plaintext ) is converted to scrambled ciphertext using an encryption key . Only at the correct destination will the encryption key be used to convert the ciphertext back into plaintext to be understood by the receiving computer. Physical Security A lock can be used to prevent access to server rooms or locations that store confidential data . Only authorised personnel with a matching key will have access. Biometric devices require the input of a human characteristic (such a fingerprint , iris or voice ). The biometric data is checked against previously inputted data in a database. Only a match will allow access to the user. Other forms of physical security include keycards , security staff , CCTV cameras and alarms . Q uesto's Q uestions 4.2 - Preventing Vulnerabilities: 1. Describe the purpose of penetration tests . [2 ] 2. Describe the purpose of anti-malware software and its different roles . [ 4 ] 3. Describe the purpose of a firewall and its different roles . [ 4 ] 4. State three rules for choosing a strong password . [ 3 ] 5. Describe the three types of access level . [6 ] 6a. Describe the purpose of encryption . [ 2 ] 6b. Explain how encryption works, using the terms plaintext , key and ciphertext . [ 4 ] 4.1 - Security Threats Theory Topics 5.1 - Operating Systems

Learn how to create and use a simple graphical user interface (GUI) in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. Python 11 - GUI Graphical User Interface In Python, you don’t have just to use a text display; you can create a GUI (Graphical User Interface ) to make programs that look professional. This page demonstrates the basic features of Python’s built-in GUI named tkinter . You can add images, labels, buttons and data entry boxes to develop interactive programs . Hyperlinked sections covered on this page: Setup: Title, Size & Background Creating Elements: Labels, Entry Boxes, Buttons, Images, Message Boxes Displaying Elements: Pack, Place, Grid Inputs & Outputs GUI Tasks Setup Setup: Title, Size & Background Firstly, import the tkinter command and set tkinter.Tk() to a variable such as window . GUI code can be quite complicated with multiple elements so it is sensible to use a comment for each section. Setting the title , size and background colour of your window is optional but can be easily set up at the start of your code. The .geometry() command sets the size of the window. The first number is the width , and the second number is the height . The .configure() command can be used to set the background colour . For a full list of compatible colours, check here . import tkinter #Setting up the Window window = tkinter.Tk() window.title( "Graphical User Interface" ) window.geometry( "400x400" ) window.configure(background = "lightblue" ) import tkinter #Setting up the Window window = tkinter.Tk() window.title( "Example Number Two" ) window.geometry( "300x400" ) window.configure(background = "darkorchid3" ) Creating Elements Creating Elements: Labels, Entry Boxes, Buttons, Radio Buttons, Images, Message Boxes Labels label1 = tkinter.Label(window, text = "Hello there" ) label1 = tkinter.Label(window, text = "Hello there" , fg = "black" , bg = "lightblue" , font = ( "Arial" , 12)) Simple label with default formatting: Label with custom formatting: No elements will appear in your window until you write code to put them there. See the 'Displaying Elements' section further down. Entry (Text) Boxes Simple entry box with default formatting: entry1 = tkinter.Entry(window ) Entry boxes will appear blank , the 'Example Text' shown in the images has been typed in. Entry box with custom formatting: entry1 = tkinter.Entry(window, fg = "blue" , bg = "gray90" , width = 12, font = ( "Arial" ,12)) Buttons The command property of a button is a subroutine that will be called when the button is pressed . The subroutine must be written above the button creation code. def ButtonPress (): #Code here runs when the button is pressed button1 = tkinter.Button(window, text = "Click Me" , fg = "black" , bg = "gold2" , command = ButtonPress) Radio Buttons The Radiobutton element is a multiple-choice option button . A variable needs to be created to track which option has been selected, in this example it is ‘choice ’. Each radio button needs to be linked to the variable and given a unique value (e.g. 0, 1, 2). The radio button with the the value of 0 will be automatically selected when the window opens . Although not shown below, the .set() command can also be used to select a specific radio button , e.g. choice.set(2) . choice = tkinter.IntVar() radio1 = tkinter.Radiobutton(window, text = "Breakfast" , variable = choice, value = 0) radio2 = tkinter.Radiobutton(window, text = "Lunch" , variable = choice, value = 1) radio3 = tkinter.Radiobutton(window, text = "Dinner" , variable = choice, value = 2) Message Boxes You need to import messagebox from tkinter before you can use message boxes . You only need to do this once in your program and it sensible to have it at the very start after you import tkinter (and any other libraries). from tkinter import messagebox tkinter.messagebox.showinfo( "Information" , "Welcome to the program!" ) tkinter.messagebox.showerror( "Error" , "There is a problem with the program." ) if (tkinter.messagebox.askyesno( "Warning" , "Have you understood the instructions?" )) == True : tkinter.messagebox.showinfo( "Warning" , "Thank you for understanding." ) else : tkinter.messagebox.showinfo( "Warning" , "Please read the instructions again." ) Yes / No Message Box Clicking Yes (True ) Clicking No (False ) Images Tkinter supports the image file types .png and .gif . The image file must be saved in the same folder that the .py file is. Resize the image in separate image editing software such as Paint to a specific size . Tkinter does not support all image file types, such as .jpg. Use an application like Microsoft Paint to save an image with a different extension like .png. photo1 = tkinter.PhotoImage(file = "hamster.png" ) photoLabel1 = tkinter.Label(window, image = photo1) An image can be turned into a clickable button rather than a label. def ButtonPress (): #Code here runs when the button is pressed photo1 = tkinter.PhotoImage(file = "hamster.png" ) button1 = tkinter.Button(window, image = photo1, command = ButtonPress) photo1 = tkinter.PhotoImage(file = "hamster.png" ) window.iconphoto( True , photo1) The icon of the window can be changed to an image . Displaying Elements: Pack, Place and Grid Pack .pack() puts the element in the centre of the window, with the next packed element immediately below. window.mainloop() should always be your last line of code in every program, after you have packed, placed or gridded your elements. Displaying Elements labelAdd.pack() buttonAdd.pack() labelMinus.pack() buttonMinus.pack() window.mainloop() Place The .place() command allows an element to be placed in specific coordinates , using x (horizontal ) and y (vertical ) axes. labelAdd.place(x = 25, y = 15) buttonAdd.place(x = 12, y = 35) labelMinus.place(x = 90, y = 15) buttonMinus.place(x = 83, y = 35) window.mainloop() Grid The .grid() command is used to create a grid system to set the row and column . Remember Python starts counting at 0 . You can use padx and pady to add extra space (x is horizontal , y is vertical ). labelAdd.grid(row = 0, column = 0, padx = 10, pady = 5) buttonAdd.grid(row = 1, column = 0, padx = 10) labelMinus.grid(row = 0, column = 1, padx = 10, pady = 5) buttonMinus.grid(row = 1, column = 1, padx = 10) window.mainloop() Inputs & Outputs Inputs and Outputs .config to Change an Element .config() overwrites the property of an element. It can be used with elements such as labels and buttons to change how they appear. label1.config(text = "Warning!" ) The example below (not showing setup and packing) adds 1 to a total variable when the button is pressed . Config is used in two ways: to display the updated total and to change the background of the label to green. def AddOne (): global total total = total + 1 labelTotal.config(text = total, bg = "green" ) total = 0 buttonAdd = tkinter.Button(window, text = "Add" , command = AddOne) Below is a similar program in full that increases or decreases and displays a total when the buttons are pressed . #Setup import tkinter window = tkinter.Tk() total = 0 #Button Presses def AddOne (): global total total = total + 1 labelTotal.config(text = total) def MinusOne (): global total total = total - 1 labelTotal.config(text = total) #Create Elements labelTotal = tkinter.Label(window, text = total, font = ( "Arial" ,14)) buttonAdd = tkinter.Button(window, text = "+" , width = 6, bg = "green" , command = AddOne) buttonMinus = tkinter.Button(window, text = "-" , width = 6, bg = "red" , command = MinusOne) #Display Elements buttonAdd.pack() buttonMinus.pack() labelTotal.pack() window.mainloop() .get to Input a Value .get() returns the value of an element such as an entry box , label or the choice variable if using radio buttons . The value of the element should be stored in a variable so it can be used elsewhere, for example: name = entryName.get() number = int (entryNumber.get()) Use int when getting a value that is an integer : The full program example below checks that the values typed into the username and password entry boxes are correct . Error Messages #Setup import tkinter from tkinter import messagebox window = tkinter.Tk() window.title( "Login" ) #Button Presses def CheckDetails (): username = entryUsername.get() password = entryPassword.get() if username == "Bob Bobson" and password == "cabbage123" : tkinter.messagebox.showinfo( "Success" , "Welcome " + username) else : tkinter.messagebox.showerror( "Invalid ", "Those details are incorrect." ) #Create Elements labelUsername = tkinter.Label(window, text = "Username:" ) labelPassword = tkinter.Label(window, text = "Password" ) entryUsername = tkinter.Entry(window) entryPassword = tkinter.Entry(window) buttonLogin = tkinter.Button(window, text = "Login" , command = CheckDetails) #Display Elements labelUsername.grid(row = 0, column = 0) entryUsername.grid(row = 0, column = 1) labelPassword.grid(row = 1, column = 0) entryPassword.grid(row = 1, column = 1) buttonLogin.grid(row = 2, column = 0) window.mainloop() .bind for Key Presses (& Close Window) .get() will run a specific function when a certain key is pressed. The name of the key must be surrounded by < > brackets and speechmarks . Any associated subroutine of a key bind will need a parameter : event has been chosen and set to None . The code below closes the window using the .destroy() command when the Esc key is pressed. def Close (event = None ): window.destroy() window.bind( "" , Close) The code below will activate the button (and display a message box) by clicking on it but also by pressing the Enter ( Return ) key . def ButtonPress (event = None ): tkinter.messagebox.showinfo( "Success" , "The button was activated" ) button1 = tkinter.Button(window, text = "Press Me" , command = ButtonPress) window.bind( "" , ButtonPress) GUI Tasks GUI Programs to Make Making a program using a GUI can be overwhelming and you must decompose the problem - take it step by step : Import tkinter and create the window (set the title, size and background colour). Create the elements you will need such as labels , buttons and entry boxes . Put the components in the window using pack , place or grid . Write the subroutines for any button presses . These are written at the top of the program after the window setup. Consider your variables - do any need to be set at the start ? Have you made them global if they’re needed within a subroutine ? Put window.mainloop() as the final line of code, only have it once. Use #comments in your code to break up the different sections, the key four sections are shown below. #Setup #Button Presses #Create Elements #Display Elements GUI Task 1 (Random Number Generator ) Generate a random number between 1 and 100 when the button is pressed and display it in a label. Extension idea: Use entry boxes to allow the user to manually input the minimum and maximum value. Example solution: GUI Task 2 (Currency Exchange ) Enter a decimal value and convert it from British pounds to American dollars. You can search for the current exchange rate. Extension idea: Show the conversion rate for other currencies such as Euros and Japanese Yen. Example solution: GUI Task 3 (Random Quote Generator ) Create a list of quotes and use the choice command from the random library to select one to be displayed in a label when the button is clicked. Extension idea: Have a separate text box and button to add more quotes to the list. Example solution: GUI Task 4 (Colour Changer ) When the button is clicked change the background colour of the button with .config to the RGB colour code in the entry box. This should be # followed by 6 hexadecimal values (0-9, A-F). Extension idea: Have an error pop up in a message box if the colour code is incorrect - it must be exactly 7 characters long and start with a hashtag. Example solutions: GUI Task 5 (Class Captain Votes ) Use radio buttons to vote for different candidates in a class vote. Use an if statement when the button is pressed to check which radio button is selected using .get() and the variable you've assigned to the radio buttons ('choice' if you've followed the code in the radio buttons section on this page). Use .config to overwrite a label's value. Remember any variables you want to use in subroutines must be globalised. Extension idea: Stop the count after a certain number - e.g. 30 votes recorded. Example solution: ⬅ Section 10 Practice Tasks 12 - Error Handling ➡

Learn about data formats such as ASCII, Unicode, CSV, fixed-width, JSON and XML and data types, including Boolean, character, date, integer, real and string. Resources based on Unit F161 (Developing Application Software) for the OCR Cambridge Advanced Nationals in Computing (H029 / H129) AAQ (Alternative Academic Qualification). Qualification: Cambridge Advanced Nationals in Computing (AAQ) Certificate: Computing: Application Development (H029 / H129) Unit: F161: Developing Application Software 2.1 - Data Formats & Types Watch on YouTube : Data Formats Data Types You need to know the characteristics , uses , advantages and disadvantages of six data formats (ASCII , Unicode , CSV , fixed-length , JSON and XML ). You also need to know the characteristics , uses , advantages and disadvantages of six data types (Boolean , character , date , integer , real and string ). What You Need to Know Data Formats ? YouTube video uploading soon Data Types ? YouTube video uploading soon Q uesto's Q uestions 2.1 - Data Formats & Types: 1. What? [2 ] 2. What? [1 ] 3. What? [1 ] 4. What? [1 ] ? D id Y ou K now? 1.3 - Storage Topic List 2.2 - Data Flow

Learn how to input strings (text) in Python. Try practice tasks and learn through text and images. Perfect for students learning GCSE Computer Science in UK schools. top Python 2a - Inputting Text Inputting Text (Strings) in Python A string is a collection of characters (letters, numbers and punctuation) such as: “Wednesday” , “Toy Story 4” or “Boeing 747” . Use the input command to ask a question and let a user input data , which is automatically stored as a string . Variable to save the answer into. Give it a suitable name based on the input. name = input ( "What is your name? " ) = What is your name? Paulina Type your answer directly into the editor and press the Enter key. Statement that is printed to the screen. Leave a space to make the output look clearer. Once an input has been saved into a variable, it can be used for other purposes, such as printing it within a sentence : name = input ( "What is your name? " ) print ( "It is nice to meet you" , name) = What is your name? Jake the Dog It is nice to meet you Jake the Dog Always choose an appropriate variable name when using inputs. colour = input ( "What is your favourite colour? " ) print ( "Your favourite colour is " + colour + "? Mine is yellow." ) = What is your favourite colour? blue Your favourite colour is blue? Mine is yellow. Inputting Text Task 1 ( Holiday) Write an input line to ask the user where they last went on holiday . Write a print line that uses the holiday variable (their answer). Example solution: Where did you last go on holiday? Scotland I hope you had a nice time in Scotland Inputting Text Task 2 ( New Neighbour) Write an input line to ask the user for a title (e.g. Mr, Mrs, Dr). Write another input line for an object . Write a print line that uses both input variables (title and object ). Example solutions: Enter a title: Dr Enter an object: Fridge I think my new neighbour is Dr Fridge Enter a title: Mrs Enter an object: Armchair I think my new neighbour is Mrs Armchair Using a Variable Within an Input To use a variable you have previously assigned a value t o within the input statement you must use + (commas will not work). drink = input ( "What would you like to drink? " ) option = input ( "What would you like with your " + drink + "? " ) print ( "Getting your" , drink , "and" , option , "now...." ) = What would you like to drink? tea What would you like with your tea? biscuits Getting your tea and biscuits now... What would you like to drink? apple juice What would you like with your apple juice? cake Getting your apple juice and cake now... Inputting Text Task 3 ( Name & Game) Ask the user what their name is. Ask the user what their favourite game is. Use their name in the input statement for their game. Print a response with their name and the game they entered. Example solutions: What is your name? Rory Hi Rory, what's your favourite game? Minecraft Rory likes Minecraft? That's nice to know. What is your name? Kayleigh Hi Kayleigh, what's your favourite game? Stardew Valley Kayleigh likes Stardew Valley? That's nice to know. ⬅ Section 1 Practice Ta sks 2b - I nputting Numbers ➡

Learn about the six main validation checks - range, type, length, format, lookup table and presence. Also, discover three verification checks - double entry, proof-reading and check digits. Based on the 2020 Eduqas (WJEC) GCSE specification. 8.5: Validation & Verification Exam Board: Eduqas Specification: 2020 What are validation and verification checks? Validation is a process to check that data is reasonable or sensible before it is accepted . Verification is the process of checking that data is correct after it has been entered. Validation Checks Range Check Checks data is within a certain range . Age: 34 203 Type Check Checks data is a certain data type . Height (in cm): 182 Two metres Format Check Checks data is entered in a certain way . Date of Birth (DD/MM/YYYY) 25/03/2001 25th March 01 Presence Check Checks that data has actually been entered and not left blank . Password: fluffythecat123 Lookup Table A table of acceptable entries , also known as a list . Length Check Checks the length of the input is within a certain amount. Telephone Number 08323877319 07383 Verification Checks Double Entry Typing in the data twice to make sure there were no spelling errors the first time. Password: fluffythecat123 flufythecat123 Proofreading Checking two copies of data to ensure they are exactly the same . Check Digit Similar to a checksum in a data packet, a check digit is calculated on barcodes to ensure the rest of the numbers are correct . Address: 11 Cherry Lane 11 Cherry Road Confirm Q uesto's Q uestions 8.4 - Validation & Verification: 1. Describe each type of validation check and give an example . a. Range Check [ 3 ] b. Type Check [ 3 ] c. Format Check [ 3 ] d. Presence Check [ 3 ] e. Lookup Table (List) [ 3 ] f. Length Check [ 3 ] 2. For the following data, suggest which validation check would be most suitable and why : a. Password [ 3 ] b. Country of Birth [ 3 ] c. Number of Tickets [ 3 ] d. Weight (in kilograms) [ 3 ] 3. Describe three types of verification check and give an example : a. Double Entry [ 3 ] b. Proofreading [ 3 ] c. Check Digit [ 2 ] 8.4 - Sorting & Searching Theory Topics 9.1 - IDE Tools

An explanation and introduction to the OCR Level 3 Cambridge Advanced National in Computing specification. This certificate (H029) or extended certificate (H129) is an Alternative Academic Qualification (AAQ). Level 3 Alternative Academic Qualification (AAQ) / Cambridge Advanced National In Computing Computing: Application Development Everything you need to know about this course: The Cambridge Advanced National in Computing: Application Development is a new course that began in September 2025 . It contains both exam and NEA (coursework ) units and focuses on developing software prototypes for applications such as websites , video games and even virtual reality . The video to the left explains all the key details of this new course, but remember, things can change so the OCR website will have the latest updates . Exam Units: Unit F160: Fundamentals of Application Development F160 YouTube Playlist Unit F161: Developing Application Software F161 YouTube Playlist These pages are based on content from the OCR Cambridge Advanced National in Computing (AAQ) specification .

Learn about searching algorithms such as linear and binary search. Also learn about sorting algorithms such as merge, bubble and insertion sorts. Based on the J277 OCR GCSE Computer Science specification (first taught from 2020 onwards). 1.3: Searching & Sorting Algorithms Exam Board: OCR Specification: J277 Watch on YouTube : Linear Search Binary Search Bubble Sort Merge Sort Insertion Sort Key features of a bubble sort: Uses an outer while loop (condition controlled ) to check no swaps have been made . Uses an inner for loop (count controlled ) to repeat through the length of the data set . Uses a flag (a Boolean value ) to track if a swap has been made and uses a temporary value to help correctly swap elements . Linear Search A linear search is the most simple search algorithm. Each data item is searched in order from the first value to the last as if they were all laid out in a line . The list does not have to be in any order before it is searched . This search is also known as a sequential search because the list is searched in a sequence from start to end. For large lists , this search is not very efficient . Binary Search A binary search is a much more efficient searching algorithm as it generally searches through fewer data and is often much quicker - especially for large data sets . In a binary search, the middle point of the data is selected with each iteration and compared to the value being searched for . When the midpoint matches the target value , it as been found and the search can stop. ! ! However there is a prerequisite of using a binary search - the list of data must already be sorted . A prerequisite is a condition that must be satisfied before an algorithm will work correctly . Merge Sort Merge sort is a sorting algorithm based on the idea of ‘divide and conquer ’. A merge sort divides a list into half , again and again until each data item is separate . Then the items are combined in the same way as they were divided , but now in the correct order . When the individual lists are all merged together as one list again, then the data is in order and the algorithm will end . Bubble Sort This algorithm is based on the comparison of adjacent data elements . Data elements are swapped if they are not in the correct order . The algorithm will only stop when a complete iteration through the data is completed with no swaps made . A bubble sort is not suitable for large sets of data . Insertion Sort The list is logically split into sorted values (on the left) and unsorted values (on the right). Starting from the left, values from the unsorted part are checked and inserted at the correct position in the sorted part. This continues through all elements of the list until the last item is reached, and sorted. Insertion sorts are efficient for small data sets but would be slow to sort large sets , compared to alternatives such as a merge sort. Key features of a linear search: A loop is used to check the first value in a list and increment by 1 , checking each value for a match to the target . Reaching the last element of the list without finding a match means the value is not included . Key features of a binary search: A midpoint , lowpoint and highpoint are calculated . A while loop is used to repeatedly compare the midpoint to a target value . The upper half or lower half of the data is ignored if the midpoint does not equal the target . Key features of a merge sort: This algorithm calls itself from within the subroutine (this is known as a recursive algorithm ). It continually splits sublists into a left side and a right side until each sublist has a length of 1 . Watch on YouTube Watch on YouTube Watch on YouTube Watch on YouTube Key features of a insertion sort: Uses an outer for loop (count controlled ) to iterate through each value in the list . Uses an inner while loop (condition controlled ) to find the current value’s correct position in the sorted part of the list . An insertion sort moves ‘ backwards ’ to find the correct position of each value, by decreasing the index within the while loop. Watch on YouTube Q uesto's Q uestions 1.3 - Searching & Sorting Algorithms: Linear Search Explain step-by-step how the number 8 would be found in the following list using a linear search : 12, 5, 3, 2, 8, 19, 14, 6 [4 ] Binary Search Explain step-by-step how the number 2 would be found in the following list using a binary search : 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 [6 ] Merge Sort Explain step-by-step how a merge sort would sort the following list of numbers: 4, 8, 5, 1, 3, 6, 7, 2 [6 ] Bubble Sort Explain step-by-step how a bubble sort would sort the following list of numbers: 3, 1, 6, 5, 2, 4 [6 ] Insertion Sort Explain step-by-step how an insertion sort would sort the following list of numbers: 5, 2, 6, 3, 1, 4 [6 ] 1.2 - Designing Algorithms Theory Topics 2.1 - Programming Fundamentals

Learn about boolean logic and expressions using NOT, AND OR and XOR, Karnaugh maps, Boolean algebra rules including De Morgan’s Laws, distribution, association, commutation and double negation, logic gate diagrams, truth tables, D-type flip flops, half adders and full adders. Based on the OCR H446 Computer Science A-Level specification. Exam Board: OCR A-Level Specification: Computer Science H446 4.3 - Boolean Algebra Watch on YouTube : Boolean Logic (NOT, AND, OR, XOR) Karnaugh maps Boolean algebra rules Logic gate diagrams Truth tables D-type flip flops Half & full adders This topic explores how the logical operations NOT , AND , OR and XOR are used to process binary data and control digital systems . It also looks at how to simplify and represent logic using Karnaugh maps , Boolean algebra rules , logic gate diagrams and truth tables . Boolean Logic Boolean logic is a form of algebra in which all values are either True (1 ) or False (0 ). It’s used in computing and digital circuits to make decisions and control the flow of programs . NOT (negation ) (¬ ) reverses the input value - 1 becomes 0 and 0 becomes 1 . AND (conjunction ) (∧ ) outputs 1 only if both inputs are 1 (e.g. 1 AND 1 = 1 , otherwise 0 ). OR (disjunction ) (v ) outputs 1 if at least one input is 1 (e.g. 1 OR 0 = 1 ). XOR (exclusive disjunction ) (v ) outputs 1 only if one input is 1 but not both (e.g. 1 XOR 1 = 0 , 1 XOR 0 = 1 ). YouTube video uploading soon Karnaugh Maps A Karnaugh map is a visual method used to simplify Boolean expressions and make logic circuits more efficient . It organises all possible input combinations into a grid , where adjacent cells differ by only one bit (following Gray code order ). By grouping together 1s (representing True outputs ) in powers of two (1 , 2 , 4 or 8 cells ), you can identify and remove redundant terms in a Boolean expression . The simplified result reduces the number of logic gates needed in a circuit, making it faster and easier to build . YouTube video uploading soon Boolean Algebra Rules Boolean algebra rules are used to simplify Boolean expressions . De Morgan’s Laws show how to distribute negation across AND and OR operations: ¬(A AND B) = (¬A OR ¬B) and ¬(A OR B) = (¬A AND ¬B) . Distributive Law allows expressions to be expanded or factored , e.g., A AND (B OR C) = (A AND B) OR (A AND C) and vice versa for OR over AND. Associative Law means the grouping of terms doesn’t affect the result . (A AND B) AND C = A AND (B AND C) and (A OR B) OR C = A OR (B OR C) . Commutative Law means the order of terms doesn’t matter in Boolean operations, e.g., A AND B = B AND A and A OR B = B OR A . With Double Negation , two NOTs cancel each other out , returning the original value , e.g., ¬¬A = A . YouTube video uploading soon Logic Gate Diagrams Logic gate diagrams are visual representations of Boolean expressions or digital circuits , showing how data flows through logic gates to produce an output . Each gate performs a basic logical operation (such as NOT , AND , OR or XOR ) and is represented by a distinct symbol . NOT AND OR XOR YouTube video uploading soon Truth Tables A truth table is used to show all possible input combinations for a logic circuit or Boolean expression , along with the resulting output for each combination . Each row in the table represents a unique set of input values (usually 0 for False and 1 for True ). The final column shows the output produced by applying the logical operations to those inputs . The number of rows in a truth table doubles with each additional input , e.g. 4 rows for 2 inputs and 8 rows for 3 inputs . YouTube video uploading soon D-Type Flip Flops A D-type flip-flop i s a sequential logic circuit that stores a single bit of data - either 0 or 1 . It has two inputs , D (data ) and CLK (clock ), and two outputs , Q and ¬Q . When a clock pulse occurs , the flip-flop copies the value of D to the Q output , and that value is held (stored ) until the next clock pulse . This makes D-type flip-flops useful for memory storage , registers and data synchronisation . Essentially, they act as a 1-bit memory cell , storing the last value of D whenever the clock signal triggers . YouTube video uploading soon Half Adders & Full Adders A half adder is a logic circuit with two inputs (A and B ) that are added to produce two outputs - S (sum ), the result of A XOR B - and C (carry ), the result of A AND B . Half adders can only add two bits and cannot handle an input carry from a previous addition . A full adder is an extension of a half adder with three inputs : A , B , and C in (a carry-in from a previous calculation ). It produces two outputs : S (sum ) (A XOR B XOR Cin ) and C out (carry out ) ((A AND B) OR (B AND Cin) OR (A AND Cin) ). Full adders can be linked together to perform multi-bit binary addition in arithmetic circuits. YouTube video uploading soon This page is under active development. Check here for the latest progress update. Q uesto's K ey T erms Boolean Logic: NOT, AND, OR, XOR, Karnaugh maps, logic gate diagrams, truth tables Boolean Algebra Rules: De Morgan’s Laws, distribution, association, commutation, double negation D-Type Flip Flops: data, clock, Q, NOT Q Adders: half adder, full adder D id Y ou K now? The word ' Boolean ' is always spelt with a capital B because it is named after George Boole , a 19th-century English mathematician . His work has become the foundation of all modern digital electronics and computing . 4.2 - Data Structures A-Level Topics 5.1 - Computing Legislation

Learn about programming constructs such as sequence, iteration and branching, recursion, local and global variables, modularity, functions and procedures, parameter passing by value and by reference, Integrated Development Environment (IDE) tools and object-oriented techniques. Based on the OCR H446 Computer Science A-Level specification. Exam Board: OCR A-Level Specification: Computer Science H446 2.1 - Programming Techniques Watch on YouTube : Programming constructs Recursion Local & global variables Modularity Integrated development environment Object-oriented programming Programming Constructs Sequence , iteration and branching (also called selection ) are the three fundamental programming constructs used to build algorithms . Sequence means that instructions run in a specific order , one after another. Iteration is the repetition of a set of instructions , usually being count-controlled , such as for loops , or condition-controlled , such as while loops or do until loops . Branching (selection ) allows a program to choose between different actions based on a condition , using structures like if , elif , else or switch . YouTube video uploading soon Recursion Recursion is where a function calls itself to solve a problem by breaking it down into smaller , simpler versions of the same problem . Recursion is often used for tasks that naturally fit a 'divide and conquer ' structure , such as quicksort and merge sort algorithms. It is also used for depth-first tree traversals and solving mathematical problems like factorials or the Fibonacci sequence . Compared to iteration , recursion can produce clearer and more elegant solutions , but it may use more memory and can be less efficient if the recursion goes too deep or lacks a proper base case (stopping condition ) , potentially running out of memory . YouTube video uploading soon Local & Global Variables Local variables are created inside a function or block and can only be accessed there , which makes programs safer and easier to debug because changes to the variable cannot affect other parts of the program ; however, they cannot store values that need to be shared across multiple functions . Global variables are declared outside all functions and can be accessed anywhere in the program , making them useful for storing information that many parts of the program need , but they can lead to errors if different functions accidentally change them and can make the program harder to maintain . YouTube video uploading soon Modularity Modularity is the practice of breaking a program into smaller , self-contained parts so each section can be developed , tested and understood independently . Functions and procedures are modular units of code: a function returns a value , while a procedure performs a task without returning a value . When data is passed into a subroutine , it can be passed by value , where a copy of the data is sent so the original cannot be changed , or passed by reference , where the subroutine receives direct access to the original data , allowing it to be modified . YouTube video uploading soon Integrated Development Environment An Integrated Development Environment (IDE ) is software that provides the tools a programmer needs to write , test and debug code in one place . It typically includes an editor for writing and formatting code , syntax highlighting to make keywords and errors easier to spot , and auto-completion to speed up coding . For debugging , an IDE often provides error diagnostics that highlight mistakes , a run-time environment to execute the program , and tools like breakpoints and step-through execution that allow the programmer to pause the program and inspect variables to find and fix bugs more easily . YouTube video uploading soon Object-Oriented Programming Object-oriented techniques are a way of designing programs by modelling them as collections of objects , each representing something with its own data and behaviours . These objects are created from classes , which act like blueprints describing the attributes (data ) and methods (actions ) an object will have . It uses key principles such as encapsulation (keeping an object’s data and methods together and protected ), inheritance (allowing classes to share and reuse features ) and polymorphism (enabling objects to behave differently ). These techniques make large programs easier to organise , maintain and extend by encouraging reusable , modular and well-structured code . YouTube video uploading soon This page is under active development. Check here for the latest progress update. Q uesto's K ey T erms Programming Constructs: sequence, iteration, selection (branching), if / elif / else, select (switch) case Recursion & Iteration: count-controlled loop, condition-controlled loop, recursion, base case Variables: local variable, global variable Modularity: function, procedure, parameter, pass by value, pass by reference Integrated Development Environment (IDE) Object Oriented Programming (OOP): class, object, method, attribute, inheritance, encapsulation, polymorphism D id Y ou K now? Roblox Studio is a free IDE for making Roblox games using the programming language Lua . With over 70m daily Roblox players , games built in Roblox Studio can reach a larger audience than many mainstream game engines . 1.1 - Computational Thinking A-Level Topics 2.2 - Computational Methods

Learn about different methods of wired and wireless connection methods including Bluetooth, satellite and microwave. Based on the 2016 OCR Cambridge Technicals Level 3 IT specification. 1.4 - Connectivity Exam Board: OCR Specification: 2016 - Unit 1 For computers to communicate with other devices and share data a form of connection is required. Wired Connections Copper Cables Copper cables are a cheaper type of wired internet connection that may be poorly insulated and therefore susceptible to electromagnetic interference . Copper cables are more likely to suffer from attenuation (network distortion ). However, they are malleable (easier to bend) and less likely to break than other cables such as fibre optic. They have a lower bandwidth - cannot transmit as much data at once - than fibre optic cables. Fibre Optic Cables Fibre optic cables are a very fast but expensive type of wired internet connection. Signals are transmitted as waves of light through a glass rod . Because of this fibre optic cables are not affected by electromagnetic interference and suffer less from attenuation . Fibre optic cables have a higher bandwidth - they can transfer more data at one time over a long distance than copper cables but they are more fragile . Wireless Connections Bluetooth Bluetooth is a temporary short-range communication between two 'paired ' devices within a limit of about 10 metres . The required close proximity is a disadvantage , however a plus is that no other hardware is required for a connection. An example is the pairing of headphones to a smartphone to listen to music. Infrared Infrared networks have largely been replaced by Bluetooth or WiFi connections because infrared networks require devices to be in direct line of sight . Infrared is still used by some devices, such as remote controls , to transmit signals to a TV, but it only works across short distances . Microwave Microwave connections use radio waves to send signals across a large area via microwave towers . It can transmit a large amount of data but antennas must be in the line of sight of each other with no obstructions . Microwave connections are affected by bad weather , leading to higher chances of attenuation (network distortion ). Laser Satellite GSM / 5G Although not common, laser connections can send data between devices that are in the line of sight of each other as long as there are no barriers . Laser connections can transmit data up to 2km but bad weather severely affects the transmission rate. Laser connections can be used in space as there are fewer barriers between the satellites. Satellite networks use point-to-multipoint communication by using satellites above the Earth's atmosphere that receive a transmission and rebroadcast them back to Earth. Because of the distance between the communication device and the satellite (roughly 35,000km), there is a delay between data transmission and it being received. See 3.4 for more information on satellite networks . GSM (Global System for Mobile communications ) is a technology for allowing mobile phones to connect to a network for calls and text messages. Advances in mobile technology are classified by generations such as 4G and 5G (the current generation). Each generation is generally faster, more secure and allows for new opportunities. See 3.4 for more information on cellular networks . Q uesto's Q uestions 1.4 - Connection Methods: 1. Compare the differences between copper and fibre optic cables (possibly in a table) by the following features: a. Price b. Bandwidth c. Inteference d. Attenuation e. Malleability / Fragility [2 each ] 2. Describe each of the different types of wireless connection . Try to list 1 advantage and 1 disadvantage of using each type. a. Bluetooth b. Infrared c. Microwave d. Laser e. Satellite f. GSM / 5G [5 each ] 1.3 - Computer System Types Topic List 1.5 - Communication Hardware