ISSB Academic & Intelligence Test Mathematics: Number Series MCQs

Practice Number Series MCQs for ISSB Academic & Intelligence Test Mathematics — topic-wise sets with solved answers.

ISSB Academic & Intelligence Test Mathematics: Number Series MCQs — sample questions

  1. Question 1

    Q1. What is the next number in the series: 2, 6, 12, 20, 30, ?

    • A) 40
    • B) 42
    • C) 44
    • D) 46

    Answer: 42

    Explanation: Differences: +4, +6, +8, +10 → next difference +12. 30 + 12 = 42. ISSB loves simple increasing-difference series.

  2. Question 2

    Q2. Next term: 2, 6, 12, 20, 30, ?

    • A) 40
    • B) 42
    • C) 44
    • D) 36

    Answer: 42

    Explanation: Differences +4,+6,+8,+10 → next +12 → 42. Sequence n(n+1). Work each step carefully; ISSB math rewards accuracy under time pressure.

  3. Question 3

    Q3. Missing number: 5, 11, 23, 47, ?

    • A) 91
    • B) 94
    • C) 95
    • D) 96

    Answer: 95

    Explanation: Pattern ×2+1: 47×2+1 = 95. Work each step carefully; ISSB math rewards accuracy under time pressure.

  4. Question 4

    Q4. Next term: 3, 9, 27, 81, ?

    • A) 162
    • B) 243
    • C) 324
    • D) 729

    Answer: 243

    Explanation: Geometric sequence ×3 each time. 81×3 = 243. Work each step carefully; ISSB math rewards accuracy under time pressure.

  5. Question 5

    Q5. Next number: 1, 4, 9, 16, 25, ?

    • A) 30
    • B) 32
    • C) 36
    • D) 49

    Answer: 36

    Explanation: Perfect squares: 1^2 through 5^2. Next is 6^2 = 36. Work each step carefully; ISSB math rewards accuracy under time pressure.

  6. Question 6

    Q6. Missing term: 7, 14, 28, 56, ?

    • A) 84
    • B) 98
    • C) 112
    • D) 128

    Answer: 112

    Explanation: Each term doubles. 56 x 2 = 112. Work each step carefully; ISSB math rewards accuracy under time pressure.

  7. Question 7

    Q7. Next term: 1, 4, 9, 16, 25, 36, ?

    • A) 42
    • B) 45
    • C) 49
    • D) 64

    Answer: 49

    Explanation: Perfect squares sequence. After 36 (6 squared) comes 49 (7 squared). Work each step carefully; ISSB math rewards accuracy under time pressure.

  8. Question 8

    Q8. Find the next number: 2, 6, 12, 20, 30, ?

    • A) 36
    • B) 40
    • C) 42
    • D) 48

    Answer: 42

    Explanation: The differences are 4, 6, 8, and 10. The next difference is 12, so 30 plus 12 equals 42.

  9. Question 9

    Q9. Find the missing term: 5, 10, 20, 40, ?, 160.

    • A) 60
    • B) 70
    • C) 80
    • D) 100

    Answer: 80

    Explanation: Each term is double the previous one. Forty times 2 is 80, and 80 times 2 is 160.

  10. Question 10

    Q10. Find the next number: 5, 10, 20, 40, ?

    • A) 60
    • B) 70
    • C) 80
    • D) 90

    Answer: 80

    Explanation: Each term is double the previous term. 40 times 2 equals 80.

  11. Question 11

    Q11. Next number: 4, 8, 16, 32, ?

    • A) 48
    • B) 56
    • C) 64
    • D) 72

    Answer: 64

    Explanation: Each term doubles. 32 times 2 equals 64. Work each step carefully; ISSB math rewards accuracy under time pressure.

  12. Question 12

    Q12. Next number: 1, 2, 4, 7, 11, ?

    • A) 15
    • B) 16
    • C) 17
    • D) 18

    Answer: 16

    Explanation: Differences are 1, 2, 3, 4, so next difference is 5. 11 plus 5 equals 16.

  13. Question 13

    Q13. Next number: 5, 10, 15, 20, ?

    • A) 22
    • B) 25
    • C) 30
    • D) 35

    Answer: 25

    Explanation: The series increases by 5 each time. 20 plus 5 equals 25.

  14. Question 14

    Q14. Next: 3, 9, 27, 81, ?

    • A) 162
    • B) 243
    • C) 324
    • D) 108

    Answer: 243

    Explanation: Each term is multiplied by 3. 81 times 3 equals 243. Work each step carefully; ISSB math rewards accuracy under time pressure.

  15. Question 15

    Q15. Next: 2, 5, 10, 17, ?

    • A) 24
    • B) 26
    • C) 28
    • D) 30

    Answer: 26

    Explanation: Differences are 3, 5, 7, so next difference is 9. 17 plus 9 equals 26.

  16. Question 16

    Q16. Next: 1, 4, 9, 16, 25, ?

    • A) 30
    • B) 36
    • C) 49
    • D) 64

    Answer: 36

    Explanation: These are squares of 1 through 5. Next is 6 squared, which is 36.

  17. Question 17

    Q17. Next: 8, 6, 9, 7, 10, 8, ?

    • A) 11
    • B) 12
    • C) 9
    • D) 10

    Answer: 11

    Explanation: Two interleaved series: 8,9,10,11 and 6,7,8. Next is 11. Work each step carefully; ISSB math rewards accuracy under time pressure.

  18. Question 18

    Q18. Next: 6, 12, 24, 48, ?

    • A) 72
    • B) 96
    • C) 84
    • D) 100

    Answer: 96

    Explanation: Each term doubles. 48 times 2 equals 96. Work each step carefully; ISSB math rewards accuracy under time pressure.

  19. Question 19

    Q19. Next: 1, 3, 6, 10, 15, ?

    • A) 20
    • B) 21
    • C) 22
    • D) 24

    Answer: 21

    Explanation: Differences are 2, 3, 4, 5, so next is 6. 15 plus 6 equals 21.

  20. Question 20

    Q20. Next: 2, 6, 12, 20, 30, ?

    • A) 40
    • B) 42
    • C) 44
    • D) 48

    Answer: 42

    Explanation: Differences are 4, 6, 8, 10, so next is 12. 30 plus 12 equals 42.

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