Number Series – Questions & Answers

Number Series Questions and Answers is about the Missing numbers in a series that you can expect for Competitive Examinations. Here you can find out practice problems from the topic Missing Number Series.

Number Series – Logical Reasoning Questions and Answers
Missing Number Series for Competitive Exams

1. Find the missing number: 32, 48, 72, 108, ——
   Answer: 162
   Explanation: 32 x 3/2 = 48
   48 x 3/2 = 72
   72 x 3/2 = 108
   108 x 3/2 = 162
2. Find the missing number: 0.5, 1.5, 4.5, 13.5, ——-
   Answer: 40.5
   Explanation: 0.5 x 3 = 1.5
   1.5 x 3 = 4.5
   4.5 x 3 = 13.5
   13.5 x 3 = 40.5
3. Find the missing number: 3, 9, 27, 81, ——–
   Answer: 243
   Explanation: 3 x 3 = 9, 9 x 3 = 27, 27 x 3 = 81, 81 x 3 = 243
4. Find the missing number: 4, 9, 13, 22, 35, ——
   Answer: 57
   Explanation: 4 + 9 = 13, 13 + 9 = 22, 22 + 13 = 35, 35 + 22 = 57
5. Find the missing number: 4, 25, 64, ——
   Answer: 121
   Explanation: Square of the numbers 2, 5, 8, 11 ———–
6. Find the missing number: 199, 195, 186, 170, ——-
   Answer: 145
   Explanation: 199 – 195 = 4, 195 – 186 = 9, 186 – 170 = 16, 170 – 25 = 145
7. Find the missing number: 3, 12, 24, 96, 192, ——
   Answer: 768
   Explanation: 3 x 4 = 12, 12 x 2 = 24, 24 x 4 = 96, 96 x 2 = 192, 192 x 4 = 768
   Multiplication with 4, 2, 4, 2, 4 ———————–
8. Find the missing number: 2, 7, 3, 26, 4, ——-
   Answer: 63
   Explanation: Consider two series 2, 3, 4, ———— and 7, 26, ———
   Find cube of 2, 3, 4 ———- and subtract 1 from each.
   i.e. Cube of 2 = 8, 8 – 1 = 7.
   Cube of 3 = 27, 27 -1 = 26
   Cube of 4 = 64, 64 – 1 = 63
9. Find the missing number: 1, 3, 7, 15, ————
   Answer: 31
   Explanation: 1 + 2 = 3, 3 + 4 = 7, 7 + 8 = 15, 15 + 16 = 31
10. Find the missing number: 5, 9, 4, 8, 3, 7, ———
    Answer: 2
    Explanation: Consider two series 5, 4, 3, ———- and 9, 8, 7, ————-
    Subtract 1 from each number, we get 5 – 1 = 4, 4 – 1 = 3, 3 – 1 = 2
11. Find the missing number: 2, 5, 9, 19, 37, ———
    Answer: 75
    Explanation: 2 x 2 + 1= 5
    5 x 2 – 1 = 10 – 1 = 9
    9 x 2 + 1 = 18 + 1 = 19
    19 x 2 – 1 = 38 – 1 = 37
    37 x 2 + 1 = 74 + 1 = 75
12. Find the missing number: 7, 12, 19, ————-
    Answer: 28
    Explanation: 7 + 5 = 12, 12 + 7 = 19, 19 + 9 = 28
    Increased by 5, 7, 9, ————-
13. Find the missing number: 3, 12, 30, 66, ———–
    Answer: 138
    Explanation: 3 + 9 = 12, 12 + 18 = 30, 30 + 36 = 66
14. Find the missing number: 16, 33, 56, 85, ——
    Answer: 120
    Explanation: 5 + 11 = 16, 16 + 17 = 33, 33 + 23 = 56, 56 + 29 = 85, 85 + 35 = 120
15. Find the missing number: 11, 19, 35, 59, ———-
    Answer: 91
    Explanation: Add 8, 16, 24, 32 —————
    11 + 8 = 19, 19 + 16 = 35, 35 + 24 = 59, 59 + 32 = 91