What Comes Next? #365

Pattern puzzle 365 card

Challenge type: What Comes Next?  ·  Difficulty: ★★★★☆ Tricky

Pixel wrote a pattern and then took a nap halfway through. Can you finish it?

Pattern: 8, 13, 21, 26, 34, 39, then a question mark. Choices: A: 50; B: 47; C: 78; D: 45.
What comes next: A, B, C or D?

The pattern in words: 8, 13, 21, 26, 34, 39, and then… what?

Your choices

  • A: 50
  • B: 47
  • C: 78
  • D: 45
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.