Computer Science
Grade 2
20 min
The Wrong Number
Identifying the incorrect number in a sequence.
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1
Introduction & Learning Objectives
Learning Objectives
Define a 'bug' as a mistake in a set of instructions.
Identify a number that breaks a simple counting pattern.
Explain why a number is 'wrong' in a sequence.
Use a step-by-step method to find a bug.
Correct a 'wrong number' bug in a simple code block loop.
Describe debugging as 'finding and fixing bugs'.
Oh no! A robot is packing toys, but it put a banana in the toy car box! 🍌🚗 How do we help the robot fix its mistake?
Today, we will be detectives! 🕵️♀️ We will learn how to find mistakes, called 'bugs', in our code. Finding and fixing bugs is called debugging!
Real-World Applications
Fixing a wrong ingredient in a cookie recipe 🍪
Finding a puzzle piece that is in the wrong spot 🧩
Correcting a...
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Key Concepts & Vocabulary
TermDefinitionExample
Bug 🐞A bug is a mistake or an error in the code. It makes the computer do something wrong.Telling a robot to jump 3 times, but it jumps 5 times.
Debug 🛠️Debugging is when we find the bug and fix it! We become bug detectives.Finding the wrong instruction and changing it so the robot jumps 3 times.
Code 💻Code is a set of instructions we give to a computer. It's like a recipe for the computer to follow.A block that says 'Move Forward' is a piece of code.
Sequence ➡️A sequence is a list of things in a special order. Each thing follows the one before it.The numbers 1, 2, 3, 4, 5 are in a sequence.
Pattern ✨A pattern is something that repeats over and over. It helps us know what comes next.Apple 🍎, Banana 🍌, Apple 🍎, Banana 🍌... The pattern is one app...
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Core Syntax & Patterns
The Pattern Detective Rule 🕵️
1. Find the pattern. 2. Check each item. 3. Find what's different.
Use this rule when you look at a list of numbers or items. Find the one that doesn't belong!
The Step-by-Step Rule 🐾
Read the code one block at a time. Watch what happens after each step.
Use this when your code is running. It helps you see exactly where the mistake happens.
4 more steps in this tutorial
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Challenging
Code: `Repeat 2 times: [Jump 3 spots]`. This makes a frog move 6 spots total. The frog needs to move 9 spots. How can you fix this by changing only ONE number?
A.Change `Repeat 2 times` to `Repeat 3 times`
B.Change `Jump 3 spots` to `Jump 4 spots`
C.Change `Repeat 2 times` to `Repeat 9 times`
D.It's impossible to fix by changing one number
Challenging
You want a robot to clap 4 times and stomp 4 times. Look at the code: `Loop A: Repeat 4 times: [Clap]`. `Loop B: Repeat 5 times: [Stomp]`. Which loop has the 'wrong number' bug?
A.Loop A has the bug
B.Loop B has the bug
C.Both loops have bugs
D.Neither loop has a bug
Challenging
A pattern should be: 🍎🍌🍎🍌. The code is `Repeat 3 times: [Show Apple], [Show Banana]`. This makes 🍎🍌🍎🍌🍎🍌. What is the wrong number?
A.The number of apples
B.The number of bananas
C.The number 3 in the 'Repeat' block
D.The number of blocks inside the loop
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