Dear Students,

Number Series is a very important part of quantitative aptitude and usually asked in all banking exams. In banking exams, it covers 4 to 5 questions which may play very important roll in selection.
So, students should aware with all type of pattern of number series asked in exams and should practice more and more on the number series. Here, we are providing some important notes and tricks for number series which will be helpful in your preparation.

Number Series

In banking exams, generally two types of number series are asked.
First one is Missing Number Series in which some numbers are given which are following certain pattern. Student is expected to find out the missing number.
Second one is Wrong Number Series in which some numbers are given but one number is wrong and does not follow the required pattern. Student is expected to find out the wrong number.
• Following patterns have been frequently asked in banking exams which are further explained below in detail.
Single stage difference
1. 3, 23, 63, ?, 303 , 623   (Ans: 143)
Pattern is:
+ 20, + 40, + 80, + 160, ………

2. 240, 205, 177, 156, 142,  ?     (Ans: 135)
Pattern is:
- 35, - 28, - 21, - 14, ………
Double stage difference
3. 12, 20, 30, 43, 60, ?      (Ans: 82)

Square Series
4. 121,  117,  108,  92,  67,  ?   (Ans:- 31)
Pattern is:

5. 8,     12,     28,     64,     128,     ?  (Ans:- 228)

Cubic Series
6. 107,     108,     100,     127,     63,     ?      (Ans:- 188)

Square/Cubic with Arithmetic
These types of series can also be solved by two/three stage difference
7. 15,     15,     17,     23,     35,     ?    (Ans:- 55)

8. 26, 63, 124, 215, ?, 511   (Ans:- 342)

9. 3,     5,     15,     45,     113,     ?   (Ans:- 243)

Multiplication/Division series
10. 32, 8, 4, 4, 8, ?   (Ans:- 32)

11. 108, 72, 36, 24, 12, ?   (Ans:- 8)
Pattern is:
÷1.5,÷2,÷1.5,÷2…………

Mix type series
12. 12, 26, 54, ?, 222, 446   (Ans:- 110)
Pattern is: ×2+2,×2+2,×2+2, ……..

13. ?, 8, 29, 152, 1073, 9668 (Ans:- 5)

Pattern is:
×1+3,×3+5,×5+7,×7+9,……..

14. 2,     17,     89,     359,     1079,     ?   (Ans:- 2159)

Practice Set
1. 1028, 1012, 980, 932, 868, ?
(a) 748
(b) 698
(c) 798
(d) 788
(e) 688

2. 6, 18, 42, 90, 186, ?
(a) 390
(b) 384
(c) 360
(d) 370
(e) 378

3. 5, 12, 26, 47, 75, ?
(a) 100
(b) 115
(c) 105
(d) 110
(e) 125

4. 36,     45,     63,     90,     126,     ?
(a) 171
(b) 165
(c) 174
(d) 161
(e) 181

5. 21,     30,     55,     104,     225,     ?
(a) 388
(b) 372
(c) 380
(d) 394
(e) 398

6. 2,     3,       6,     15,     45,       ?
(a) 1575
(b) 2575
(c) 157.5
(d) 257.5
(e) 158.5

7. 12,     13,     22,     47,     96,     ?
(a) 177
(b) 217
(c) 196
(d) 160
(e) 172

8. 5,     6,     14,     45 ,     184,     ?
(a) 960
(b) 925
(c) 980
(d) 985
(e) 975

9. 9,     5,     6,     ? ,     23,     60,     183,
(a) 10.5
(b) 12
(c) 9.5
(d) 10
(e) 9

10. 5,     6,     21,     110,     777,     ?
(a) 6993
(b) 4668
(c) 7002
(d) 7780
(e) 8558

S1. Ans.(d)
Sol.
Pattern is:
1028 – 1 × 16 = 1012
1012 – 2 × 16 = 980
980 – 3 × 16 = 932
932 – 4 × 16 = 868
868 – 5 × 16 = 788

S2. Ans.(e)
Sol.

S3. Ans.(d)
Sol.

S4. Ans.(a)
Sol.

S5. Ans.(d)
Sol.

S6. Ans.(c)
Sol. ×1.5,×2,×2.5,×3…..

S7. Ans.(a)
Sol.

S8. Ans.(b)
Sol.

S9. Ans.(a)
Sol.

S10. Ans.(c)
Sol.