**SSC CHSL Topic Wise Study Material – Quantitative Aptitude – Number Series**

Contents

SSC CHSL Study MaterialSSC CHSL Previous PapersSSC CHSL Practice Workbook

A number series is a sequence of many numbers written from left to right in a certain pattern. They always follow some pattern or the other specific rules we just have to recognize the rule or pattern to solve these questions.

In SSC (10+2) Examination, mainly two types of questions are asked from this chapter

• Find the missing term or next term in given series.

• Find the wrong term in given series.

Some of the specific rules or pattern of series are discussed in this chapter.

**I. Prime Number Series**

In this type of series, a series is made by using prime numbers and arranging them in different patterns.

**Example** Find out the next term in the series?

7,11,13,17,19,…

(a) 21

(b) 23

(c) 27

(d) 25

**Answer:**

(b) Given series is a consecutive prime number series. Therefore, next term in series will be 23.

**II. Multiple Series**

In this type of series, proceeds as a multiple of a specific number.

**Example** Find out the missing term in the series 4, 8, 16, 32, 64, ?, 256.

(a) 120

(b) 128

(c) 144

(d) 156

**Answer:**

(b) Here, every next number is double the previous number.

Required number = 64 x 2 = 128

**III. Division Series**

Similar to multiple series but here in place of multiples, numbers in series are divided by some specific number.

**Example** Find out the missing term in the series 80, 200, 500, ?, 3125.

(a) 1250

(b) 1350

(c) 1000

(d) 1225

**Answer:**

(a) 80 x 5/2= 200, 200 x 5/2 = 500, 500 x 5/2 = 1250, 1250 x 5/2 = 3125

Hence, missing term is 1250.

**IV. Difference or Addition Series**

In this type, the pattern followed is of adding or subtracting a specific number.

**Example** The ninth term of the sequence** ssc (10+2) 2010**

0, 3, 8, 15, 24, 35,… is

(a) 63

(b) 70

(c) 80

(d) 99

**Answer:**

**Example** Find out the missing term in the series 108, 99,90,81,9,63.

(a) 83

(b) 73

(c) 72

(d) 75

**Answer:**

(c) Here, every next number is 9 less than the previous number.

Required number = 81-9=72

**V.n² Series**

The pattern followed in this type of series is squaring the number in a specific pattern.

Example Find out the missing term in the series 4, 16, 36, 64, ?, 144.

(a) 72

(b) 96

(c) 100

(d) 92

**Answer:**

**VI. (n² +1) Series**

Very similar to n2 series but here 1 is added to the square term to form the series.

**Example** Find out the missing term in the series 10, 17, 26, 37, ?, 65.

(a) 55

(b) 52

(c) 54

(d) 50

**Answer:**

**Reference Corner**

**1. Find the missing number in the given series.SSC (10+2)2014**

**6, 42, ?, 1260, 5040, 15120, 30240**

(a) 546

(b) 424

(c) 252

(d) 328

**Answer:**

**2.Find the missing number in the given series SSC (10 + 2) 2014**

**7, 8, 18, ?, 232, 1165**

(a) 84

(b) 42

(c) 57

(d) 36

**Answer:**

**Practice Exercise**

**1. What will come on the place of question mark (?) in the given series?**

**39, 52, 78, 117, 169,9**

(a) 246

(b) 182

(c) 234

(d) 256

**2. What should come in place of question mark (?) in the following series?**

**1, 2, 6, 21, 88, 445,?**

(a) 2230

(b) 2670

(c) 2580

(d) 2676

**3.Find the wrong number in the given series.**

**142, 119, 110, 83, 65, 59, 52**

(a) 12

(b) 24

(c) 46

(d) 70

**4.Find the wrong number in the given series.**

**2, 10, 18, 54, 162, 486, 1458**

(a) 2

(b) 4

(c) 6

(d) 12

**5. Find the number which will come on the place of question mark (?) in the given series.**

**20, 21, 25, 34, 50, ?, 111**

(a) 70

(b) 65

(c) 60

(d) 75

**6. What will come on the place of question mark (?) in the given series?**

**4, 8, 24, 60, ?, 224**

(a) 178

(b) 96

(c) 109

(d) 124

**7. Find the missing number in the given series.**

**2, 5, 7, ?, 13, 17, 19, 23**

(a) 9

(b) 11

(c) 8

(d) 10

**8. What will come on the place question mark ? in the given series?**

**7, 4, 5, 9, ?, 52.5, 160.5**

(a) 32

(b) 16

(c) 14

(d) 20

**9. Find the missing number in the given series. 9, 62, ?, 1854, 7415, 22244**

(a) 433

(b) 309

(c) 406

(d) 371

**10. Find the missing number in the given series.**

**6, 9, 15, 27, 51,?**

(a) 84

(b) 99

(c) 123

(d) 75

**11. Find the wrong number in the given series.**

**22, 23, 27, 36, 58, 77**

(a) 77

(b) 58

(c) 36

(d) 22

**12. Find the wrong number in the given series.**

**12,12,18,48,180,1080**

(a) 180

(b) 12

(c) 18

(d) 48

**Answers**

**Hints & Solutions**

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