Number Series Practice Questions

1) Question: Find the missing number in the following series

98, 187, 94, 183, 90, 179, ?

A) 86

B) 75

C) 96

D) 84

Answer: A) 86

Solution:

98+89=187
187-93=94
94+89=183
183-93=90
90+89=179
179-93= 86

2) Question: Find the missing number in the following series

62, 124, 310, ?, 3255, 13020

A) 950

B) 850

C) 930

D) 1050

Answer: C) 930

Solution: 

62*2=124
124*2.5=310
310*3= 930
930*3.5=3255
3255*4=13020

3) Question: Find the missing number in the following series

2, 13, 64, 257, 770, ?, 1540

A) 1541

B) 1524

C) 1452

D) 1356

Answer: A) 1541

Solution: 

2 × 6 + 1= 13
13 × 5 – 1 = 64
64 × 4 + 1 = 257
257 × 3 – 1 = 770
770 × 2 + 1 = 1541
1541 × 1 - 1= 1540

4) Question: Find the missing number in the following series

85, 110, 94, 103, 99, ?

A) 130

B) 100

C) 126

D) 148

Answer: B) 100

Solution: 

85 + 52 = 110
110 – 42 = 94
94 + 32 = 103
103 – 22 = 99
99 + 12 = 100

5) Question: Find the missing number in the following series

23, 11.5, 11.5, 23, ?, 736

A) 96

B) 124

C) 104

D) 92

Answer: D) 92

Solution:

23 * 0.5 = 11.5
11.5 * 1 = 11.5
11.5 * 2 = 23
23 * 4 = 92
92 * 8 = 736

6) Question: Find the wrong number in the following series

17, 8, 9, 12, 26, 62, 190.5 

A) 17

B) 62

C) 12

D) 9

Answer: B) 62

Solution: 

17 * 0.5 – 0.5 = 8
8 * 1 + 1 = 9
9 * 1.5 – 1.5 = 12
12 * 2 + 2 = 26
26 * 2.5 – 2.5 = 62.5
62.5 * 3 + 3 = 190.5 

7) Question: Find the wrong number in the following series

1333, 1731, 2201, 2749, 3378 

A) 1333

B) 1731

C) 3378 

D) 2201

Answer: C) 3378 

Solution:

11³ + 2 = 1333
12³ + 3 = 1731
13³ + 4 = 2201
14³ + 5 = 2749
15³ + 6 = 3381

8) Question: Find the wrong number in the following series

7, 29, 5, 31, 3, 33, 2

A) 7

B) 29

C) 5

D) 2

Answer: D) 2

Solution:

The pattern is +22, –24, +26, –28, +30, -32
∴ Wrong term = 2 ≠ 33-32 = 1  

9) Question: Find the wrong number in the following series

15, 18, 42, 125, 506, 2537

A) 15

B) 125

C) 42

D) 506

Answer: C) 42

Solution: 

15 * 1 + 3 = 18
18 * 2 + 4 = 40
40 * 3 + 5 = 125
125 * 4 + 6 = 506
506 * 5 + 7 = 2537 

10) Question: Find the wrong number in the following series

64, 32, 48, 110, 420, 1890 

A) 64

B) 110

C) 420

D) 48

Answer: B) 110

Solution:

64 * 0.5 = 32
32 * 1.5 = 48
48 * 2.5 = 120
120 * 3.5 = 420
420 * 4.5 = 1890

Click Here To Practice More Number Series Questions - Free PDF