Number Series Practice Test Questions for Logical Reasoning -- Free Practice

Question 1

Find out the next number in the following series: 7, 11, 13, 17, 19, 23, 25, 29, ?

A

30✓✗

B

31✓✗

C

32✓✗

D

33✓✗

Explanation

The series follows an alternating pattern of +4, +2:
7 (+4) 11 (+2) 13 (+4) 17 (+2) 19 (+4) 23 (+2) 25 (+4) 29 (+2) ?
Following the pattern, the next difference is +2: 29 + 2 = 31

Question 2

Find the missing term in the following series: 6, 13, 25, 51, 101, ?

A

201✓✗

B

202✓✗

C

203✓✗

D

205✓✗

Explanation

The series alternates between ×2+1 and ×2-1:
6 ×2+1→ 13 ×2-1→ 25 ×2+1→ 51 ×2-1→ 101 ×2+1→ ?
101 × 2 + 1 = 203

Question 3

Find the missing term in the following series: 28, 33, 31, 36, 34, 39, ?

A

48✓✗

B

37✓✗

C

54✓✗

D

62✓✗

Explanation

The series alternates between +5 and -2:
28 (+5) 33 (-2) 31 (+5) 36 (-2) 34 (+5) 39 (-2) ?
39 - 2 = 37

Question 4

In the following series, which number will replace the question mark:
23, 29, 31, 37, 41, 43, ?

A

45✓✗

B

53✓✗

C

47✓✗

D

49✓✗

Explanation

The series is a sequence of consecutive prime numbers: 23, 29, 31, 37, 41, 43 are all prime.
The next prime number after 43 is 47.

Question 5

Find the missing term: 18, 24, 21, 27, ?, 30, 27

A

33✓✗

B

30✓✗

C

24✓✗

D

21✓✗

Explanation

The series alternates between +6 and -3:
18 (+6) 24 (-3) 21 (+6) 27 (-3) ? (+6) 30 (-3) 27
Missing term = 27 - 3 = 24

Question 6

Find the missing term: 5, 7, 11, ?, 35, 67

A

23✓✗

B

28✓✗

C

30✓✗

D

19✓✗

Explanation

The differences between consecutive terms double each time:
7-5=2, 11-7=4, next difference=8, 35-?=16, 67-35=32
Missing term = 11 + 8 = 19 (and indeed 35-19=16, 67-35=32, confirming the doubling pattern)

Question 7

Find the next term of the series: 4, 9, 16, 25, 36, 49, ?

A

1✓✗

B

9✓✗

C

20✓✗

D

64✓✗

Explanation

The series is consecutive perfect squares: 2², 3², 4², 5², 6², 7²
Next term = 8² = 64

Question 8

Find the next term of the series: 1, 3, 4, 8, 15, 27, ?

A

37✓✗

B

44✓✗

C

50✓✗

D

55✓✗

Explanation

Each term is the sum of the previous three terms (a tribonacci-style pattern):
1 + 3 + 4 = 8 ✓
3 + 4 + 8 = 15 ✓
4 + 8 + 15 = 27 ✓
Next term = 8 + 15 + 27 = 50

Question 9

Find the next term of the series: 1, 5, 14, 30, 55, 91, ?

A

130✓✗

B

140✓✗

C

150✓✗

D

160✓✗

Explanation

Each term is a cumulative sum of squares: 1², 1²+2², 1²+2²+3², and so on:
1, 1+4=5, 5+9=14, 14+16=30, 30+25=55, 55+36=91
Next term = 91 + 7² = 91 + 49 = 140

Question 10

Find the wrong term of the series 121, 143, 165, 186, 209

A

143✓✗

B

165✓✗

C

186✓✗

D

209✓✗

Explanation

The series increases by 22 each time: 121, 143, 165, 187, 209
186 does not fit this pattern; the correct term should be 187

Question 11

Find the missing term: 7, 26, 63, 124, 215, 342, ?

A

391✓✗

B

421✓✗

C

481✓✗

D

511✓✗

Explanation

Each term follows n³ - 1: 2³ - 1 = 7, 3³ - 1 = 26, 4³ - 1 = 63, 5³ - 1 = 124, 6³ - 1 = 215, 7³ - 1 = 342
Next term = 8³ - 1 = 511

Question 12

Find the next number in the series: 2, 5, 11, 23, 47, ...

A

84✓✗

B

95✓✗

C

98✓✗

D

105✓✗

Explanation

Each term follows the pattern ×2 + 1: 2 × 2 + 1 = 5, 5 × 2 + 1 = 11, 11 × 2 + 1 = 23, 23 × 2 + 1 = 47
Next term = 47 × 2 + 1 = 95

Question 13

Find the missing term of the following series: 3, 15, ?, 63, 99, 143

A

27✓✗

B

35✓✗

C

45✓✗

D

56✓✗

Explanation

Each term follows (2n-1)(2n+1) for n = 1, 2, 3...: 1×3 = 3, 3×5 = 15, 5×7 = 35, 7×9 = 63, 9×11 = 99, 11×13 = 143
Missing (3rd) term = 35

Question 14

Find the missing term of the following series: 3, 7, 15, ?, 63, 127

A

30✓✗

B

31✓✗

C

47✓✗

D

52✓✗

Explanation

Each term follows the pattern ×2 + 1: 3 × 2 + 1 = 7, 7 × 2 + 1 = 15, 15 × 2 + 1 = 31, 31 × 2 + 1 = 63, 63 × 2 + 1 = 127
Missing term = 31