Number Sequence
Spot the pattern and find the next number. Difficulty scales the trickiness; answer shows in the app.
Example
5, 10, 20, 40, __
What number comes next?
Answer (in the app): 80 — multiply by 2
🔒 The answer is never printed — it shows in the app (and via the page's QR code).
How to play
- Look at how the numbers change from one to the next. The jump might be adding, multiplying, or something trickier.
- Work out the rule, then write the next number.
- Check your answer in the app.
How it works
Fully procedural number pattern. Little kids count by 2s, 5s, and 10s; the middle levels add growing jumps, multiplying, squares, primes, and Fibonacci; the top levels use IQ-test rules like two woven sequences, jumps that are squares or primes, triple-then-subtract, and n³ − n. Harder levels show more numbers so there is exactly one sensible answer. Infinite variety, no content bank.
What you can set
- Appropriateness dial (kindergarten → adult) — tune it per card. Picks the rule families and how big the numbers get. From 13 up, it never prints a plain add-or-multiply pattern.
Age dial (1–20): 1–4: small steps · 5–8: bigger steps, doubling · 9–12: squares, growing jumps · 13+: multi-rule and prime patterns.