Number Series

What you'll learn

Crack SSC-CGL number series questions by learning the common patterns - differences, ratios, squares, and mixed rules - with a reliable step-by-step detective method.

This chapter has

Number Series — solved practice questions

6 SSC / Banking General Intelligence & Reasoning questions with step-by-step solutions. Attempt each, then reveal the answer.

1. Q1easy

   Find the next number: 2, 4, 6, 8, ?

   • A9
   • B10
   • C11
   • D12
   Show answer & solution

   Correct answer: (B) 10

   Add 2 each time → 8 + 2 = 10.

2. Q2medium

   Find the next number: 1, 4, 9, 16, ?

   • A20
   • B24
   • C25
   • D30
   Show answer & solution

   Correct answer: (C) 25

   These are perfect squares (1², 2², 3², 4²), so next is 5² = 25.

3. Q3easy

   Find the next number: 3, 6, 12, 24, ?

   • A36
   • B48
   • C30
   • D40
   Show answer & solution

   Correct answer: (B) 48

   Each term is doubled → 24 × 2 = 48.

4. Q4medium

   Find the next number: 1, 1, 2, 3, 5, ?

   • A7
   • B8
   • C9
   • D10
   Show answer & solution

   Correct answer: (B) 8

   Fibonacci — each term is the sum of the two before it → 3 + 5 = 8.

5. Q5easy

   Find the missing number: 5, 10, 15, ?, 25

   • A18
   • B20
   • C22
   • D24
   Show answer & solution

   Correct answer: (B) 20

   Add 5 each time → after 15 comes 20.

6. Q6hard

   Find the next number: 2, 5, 10, 17, ?

   • A24
   • B26
   • C28
   • D25
   Show answer & solution

   Correct answer: (B) 26

   Differences are 3, 5, 7 (odd numbers); next difference is 9 → 17 + 9 = 26.

Want the full set? Practise all 6 Number Series questions →