Challenge type: What Comes Next? · Difficulty: ★★★★☆ Tricky
Beep’s lights are blinking in a pattern, but one light is hiding. Can you work out what it should be?
The pattern in words: 3, 4, 12, 13, 21, 22, and then… what?
Your choices
- A: 29
- B: 30
- C: 31
- D: 20
Need a hint?
The gaps between the numbers are not all the same, but they do follow a pattern of their own.
Did you know? When coders spot a pattern, they can write a loop: a few lines of code that repeat the rule as many times as they like. The answer page shows this pattern as real Python code!
For teachers and grown-ups
Skills practised: Pattern recognition, abstraction, and predicting the next step of a rule.
The big idea: Spotting a pattern lets a programmer replace lots of repeated steps with one short loop.
Questions to ask:
- What is the rule, in your own words?
- How many items repeat before the pattern starts again?
- What would the 20th item be? How could you work it out without drawing them all?
Take it further: Children invent their own pattern with a hidden rule and challenge a partner to find it.