Brain teasers2 min read

How to play Number Sequence

Look at a row of numbers, work out the pattern, and pick the number that comes next.

Goal

Work out the rule behind a series of numbers and pick the next one.

A series of numbers appears with a “?” at the end.
Work out the rule. It may add or multiply, use squares, primes or Fibonacci-style rules, or weave two series together.
Pick the number you think comes next from the four options.
After answering, press “Why was I wrong?” (or “Show the rule”) to see the rule and the working, including why your wrong answer was tempting.
On Expert, each question has a 12-second countdown.

2, 4, 6, 8, ? : each number goes up by 2, so the next is 10.

3, 6, 12, 24, ? : each number doubles, so the next is 48.

Check the differences between neighbouring numbers first. If they change, check the differences of those differences.
If the numbers grow very fast, try multiplying, squaring or a recurrence rule such as Fibonacci.
If the series looks irregular, it may be two series interleaved: read every second number.
Harder levels use pattern families such as quadratics, Lucas numbers, primorials and Catalan numbers.

Every correct answer is worth 100 points, scaled by difficulty (Easy ×0.8, Medium ×1, Hard ×1.3, Expert ×1.6).
Answering within 3 seconds adds a 25-point speed bonus.
Each answer in a row adds a 15-point streak bonus, up to 10 in a row.
Using a hint halves the points for that answer and skips the bonuses. Hints are only available on Easy and Medium.
Your score, streak and achievements are saved to your account when the game ends.

Classic

A fixed number of rounds, then a results screen.

Endless

Keep playing until you press Quit.

Time Attack

Fit in as many rounds as you can before the clock runs out.

Survival

Play until you run out of lives or make the game-ending mistake.