"SSC CGL Number Series Questions 2025 | 20 MCQs with Solutions PDF"

SSC CGL Tier 1 - Reasoning

Number Series: Complete Pattern Guide

20 Practice Questions | Easy • Medium • Hard

􏰀 EASY LEVEL (Questions 1-7) Question 1

Find the next number in the series: 2, 4, 6, 8, 10, ?

(A) 11 (B) 12 (C) 13 (D) 14

Answer: (B) 12

Explanation:

Pattern: Arithmetic Progression with common difference 2

2+2=4
4+2=6
6+2=8
8 + 2 = 10
10 + 2 = 12
The series consists of consecutive even numbers Answer: 12

Question 2

Find the missing number: 5, 10, 15, 20, ?, 30

(A) 22 (B) 24 (C) 25 (D) 26

Answer: (C) 25

Explanation:

Pattern: Multiples of 5 (Arithmetic Progression w

5=5×1
10 = 5 × 2
15 = 5 × 3
20 = 5 × 4
? = 5 × 5 = 25 30 = 5 × 6 Answer: 25

ith common difference 5)

Question 3

Find the next number: 1, 4, 9, 16, 25, ?

(A) 30 (B) 32 (C) 36 (D) 40

Answer: (C) 36

Explanation:

Pattern: Perfect Squares (n2)

1 = 12
4 = 22
9 = 32
16 = 42
25 = 52
? = 62 = 36 Answer: 36

Question 4

Find the next number: 3, 6, 9, 12, 15, ?

(A) 16 (B) 17 (C) 18 (D) 19

Answer: (C) 18

Explanation:

Pattern: Multiples of 3 (Arithmetic Progression w

3=3×1 6=3×2 9=3×3
12 = 3 × 4
15 = 3 × 5
? = 3 × 6 = 18 Answer: 18

ith common difference 3)

Question 5

Find the next number: 2, 4, 8, 16, 32, ?

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

Answer: (C) 64

Explanation:

Pattern: Geometric Progression (each term = previous × 2)

2×2=4
4×2=8
8 × 2 = 16
16 × 2 = 32
32 × 2 = 64
Also can be seen as: 21, 22, 23, 24, 25, 26 = 64 Answer: 64

Question 6

Find the missing number: 1, 8, 27, ?, 125

(A) 54 (B) 64 (C) 72 (D) 81

Answer: (B) 64

Explanation:

Pattern: Perfect Cubes (n3)

1 = 13
8 = 23
27 = 33
? = 43 = 64 125 = 53 Answer: 64

Question 7

Find the next number: 10, 20, 30, 40, 50, ?

(A) 55 (B) 60 (C) 65 (D) 70

Answer: (B) 60

Explanation:

Pattern: Multiples of 10 (Arithmetic Progression with common difference 10)

10 + 10 = 20 20 + 10 = 30 30 + 10 = 40 40 + 10 = 50 50 + 10 = 60 Answer: 60

􏰁 MEDIUM LEVEL (Questions 8-15)

Question 8

Find the missing number: 3, 6, 11, 18, 27, ?

(A) 36 (B) 38 (C) 40 (D) 42

Answer: (B) 38

Explanation:

Pattern: Add consecutive odd numbers (3, 5, 7, 9, 11)

3+3=6
6 + 5 = 11
11 + 7 = 18
18 + 9 = 27
27 + 11 = 38
The difference increases by 2 each time Answer: 38

Question 9

Find the next number: 2, 3, 5, 8, 12, ?

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

Answer: (C) 17

Explanation:

Pattern: Add consecutive natural numbers (1, 2,

2+1=3 3+2=5 5+3=8
8 + 4 = 12 12 + 5 = 17 Answer: 17

3, 4, 5)

Question 10

Find the missing number: 5, 11, 23, 47, ?, 191

(A) 85 (B) 91 (C) 95 (D) 97

Answer: (C) 95

Explanation:

Pattern: (Previous number × 2) + 1

5 × 2 + 1 = 11 11 × 2 + 1 = 23 23 × 2 + 1 = 47 47 × 2 + 1 = 95 95 × 2 + 1 = 191 Answer: 95

Question 11

Find the next number: 1, 1, 2, 3, 5, 8, ?

(A) 11 (B) 12 (C) 13 (D) 15

Answer: (C) 13

Explanation:

Pattern: Fibonacci Series (each term = sum of previous two terms)

1+1=2
1+2=3
2+3=5
3+5=8
5 + 8 = 13
This is the famous Fibonacci sequence Answer: 13

Question 12

Find the missing number: 7, 14, 28, 56, ?, 224

(A) 96 (B) 108 (C) 112 (D) 120

Answer: (C) 112

Explanation:

Pattern: Geometric Progression (each term = previous × 2)

7 × 2 = 14
14 × 2 = 28 28 × 2 = 56 56 × 2 = 112 112 × 2 = 224 Answer: 112

Question 13

Find the next number: 11, 13, 17, 19, 23, ?

(A) 27 (B) 28 (C) 29 (D) 31

Answer: (C) 29

Explanation:

Pattern: Prime Numbers Series

11 → Prime number
13 → Prime number
17 → Prime number
19 → Prime number
23 → Prime number
Next prime after 23 is 29 Answer: 29

Question 14

Find the missing number: 2, 6, 12, 20, 30, ?

(A) 38 (B) 40 (C) 42 (D) 44

Answer: (C) 42

Explanation:

Pattern: n(n+1) where n = 1, 2, 3, 4, 5, 6

1×2=2
2×3=6
3 × 4 = 12
4 × 5 = 20
5 × 6 = 30
6 × 7 = 42
Pattern: Product of consecutive natural numbers Answer: 42

Question 15

Find the next number: 4, 9, 16, 25, 36, ?

(A) 45 (B) 47 (C) 49 (D) 50

Answer: (C) 49

Explanation:

Pattern: Squares of consecutive numbers startin

4 = 22
9 = 32
16 = 42
25 = 52
36 = 62
? = 72 = 49 Answer: 49

g from 2

􏰂 HARD LEVEL (Questions 16-20)

Question 16

Find the missing number: 2, 5, 10, 17, 26, ?, 50

(A) 35 (B) 37 (C) 39 (D) 41

Answer: (B) 37

Explanation:

Pattern: n2 + 1 where n = 1, 2, 3, 4, 5, 6, 7

2 = 12 + 1
5 = 22 + 1
10 = 32 + 1
17 = 42 + 1
26 = 52 + 1
? = 62 + 1 = 36 + 1 = 37 50 = 72 + 1 = 49 + 1 Answer: 37

Question 17

Find the next number: 3, 12, 27, 48, 75, ?

(A) 96 (B) 102 (C) 108 (D) 112

Answer: (C) 108

Explanation:

Pattern: 3 × n2 where n = 1, 2, 3, 4, 5, 6

3 = 3 × 12
12 = 3 × 22 = 3 × 4
27 = 3 × 32 = 3 × 9
48 = 3 × 42 = 3 × 16
75 = 3 × 52 = 3 × 25
? = 3 × 62 = 3 × 36 = 108 Answer: 108

Question 18

Find the missing number: 1, 4, 10, 22, 46, ?, 190

(A) 84 (B) 88 (C) 92 (D) 94

Answer: (D) 94

Explanation:

Pattern: (Previous number × 2) + 2

1×2+2=4
4 × 2 + 2 = 10 10 × 2 + 2 = 22 22 × 2 + 2 = 46 46 × 2 + 2 = 94 94 × 2 + 2 = 190 Answer: 94

Question 19

Find the next number: 6, 13, 28, 59, ?

(A) 118 (B) 120 (C) 122 (D) 124

Answer: (C) 122

Explanation:

Pattern: (Previous number × 2) + 1

6 × 2 + 1 = 13
13 × 2 + 2 = 28
28 × 2 + 3 = 59
Wait, let me recalculate: 6 × 2 + 1 = 13 ✓

13 × 2 + 2 = 28 ✓
28 × 2 + 3 = 59 ✓
59 × 2 + 4 = 122
The constant being added increases by 1 each time (1, 2, 3, 4) Answer: 122

Question 20

Find the missing number: 8, 27, 64, 125, ?, 343

(A) 196 (B) 200 (C) 212 (D) 216

Answer: (D) 216

Explanation:

Pattern: Perfect cubes starting from 23

8 = 23
27 = 33
64 = 43
125 = 53
? = 63 = 216 343 = 73 Answer: 216

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