Puzzle · Aptitude

Number Series

Spot the pattern and type the next number. Ten questions per round, and they get harder as you go. Faster answers earn bonus points.

Question 1

How to solve number series questions

Number series appear in almost every aptitude test: campus placements, bank exams (IBPS, SBI), SSC and company hiring tests. Most series follow one of a few patterns. Try these checks in order:

  1. Differences: subtract each number from the next. Equal differences mean you add the same amount every time (2, 5, 8, 11: add 3).
  2. Differences of differences: if the gaps themselves grow steadily (1, 3, 6, 10: gaps 2, 3, 4), the next gap continues that pattern.
  3. Ratios: if the numbers grow fast, divide each by the one before. Equal ratios mean you multiply (3, 6, 12, 24: times 2).
  4. Squares and cubes: learn 1², 2² … 20² and 1³ … 10³ by heart, because they show up often, sometimes with +1 or −1.
  5. Two series in one: if nothing fits, look at every second number. Many series alternate between two separate patterns.
  6. Previous two numbers: each term might be the sum of the two before it, as in the Fibonacci series.