Every programmer writes bugs — the skill is finding them. Year 3 coders debug longer robot programs on bigger grids, tracing each step to find the one arrow that sends the robot the wrong way.
What your child will learn
- Trace a long program step by step
- Find the one step that stops a program working
- Say what the step should be instead
Trace, don’t guess
With six or seven steps, guessing rarely works. Put a finger on the start and follow each arrow in turn. The moment the robot goes somewhere it shouldn’t, you’ve found the bug.
Example questions
Here are a few questions like the ones in the first quest. Can you solve them?
1. The robot should reach the star, but one step has a bug. Which step is wrong?
- Step 1
- Step 2
- Step 3
- Step 4
Show answer
Answer: Step 1. Step 1 should be ↑ instead of ↓. Fix that one arrow and the robot reaches the star!
2. The robot should reach the star, but one step has a bug. Which step is wrong?
- Step 1
- Step 2
- Step 4
- Step 5
Show answer
Answer: Step 5. Step 5 should be → instead of ↓. Fix that one arrow and the robot reaches the star!
3. The robot should reach the star, but one step has a bug. Which step is wrong?
- Step 1
- Step 2
- Step 3
- Step 4
Show answer
Answer: Step 1. Step 1 should be → instead of ↑. Fix that one arrow and the robot reaches the star!
Tips for grown-ups
- Write directions to a room in your house with one deliberate mistake, and ask your child to find it.
- Praise careful checking more than speed.