SSC CGL Exam  >  SSC CGL Notes  >  Quantitative Aptitude for SSC CGL  >  Important Formulas: Number Series

Important Formulas: Number Series | Quantitative Aptitude for SSC CGL PDF Download

Number Series Formulas

A number series is a progression of numbers arranged based on a specific system or rule, without adhering to a particular order. The task involves identifying the underlying system or rule governing a given series and using it to determine the subsequent numbers.

For Example : 3, 9, 27, 81 ?
It is Geometric series.
Each term is Multiplied by 3.
So , 81 x 3 = 243

Important Formulas: Number Series | Quantitative Aptitude for SSC CGL

Formulas for Number Series
Important Formulas: Number Series | Quantitative Aptitude for SSC CGL

MCQ: Number Series - 2
Start Test
Start Test

Types of number series

Types of Number Series is given below:

  • Arithmetic Sequence: A sequence in which every term is created by adding or subtracting a definite number to the preceding number is an arithmetic sequence.
  • Geometric Sequence: A sequence in which every term is obtained by multiplying or dividing a definite number with the preceding number is known as a geometric sequence.
  • Harmonic Sequences: A series of numbers is said to be in harmonic sequence if the reciprocals of all the elements of the sequence form an arithmetic sequence.
  • Fibonacci Numbers: Fibonacci numbers form an interesting sequence of numbers in which each element is obtained by adding two preceding elements and the sequence starts with 0 and 1. 

Add Up Series

Add up Series +

  • Probability of asking – Very Low
  • Difficulty – Low
  • Reason – to Introduce Concept

These problems are never asked they are very easy, we are talking about them to introduce the number series from basic.

  1. Rule – Just Add a number ‘N’ to the last number.
  2. E.g. – 5, (5 + 3 = 8), (8 + 3 = 11), ( 11 + 3= 14) ….
  3. Result –  5, 8, 11, 14, 17 ……..

Add up Series –

  • Probability of asking – Very Low
  • Difficulty – Low
  • Reason – to Introduce Concept
  1. Rule : Just Add a number ‘N’ to the last number.
  2. E.g. : 4, (4 – 5 =  (-1)), (-1 -5 = -6), ( -6 – 5 = -11) ….
  3. Result : 4, -1, -6, -11, -16 ……..

Square up and Square Add up Series


Square up and Square Add up Series +

Square up +(Easy to Identify)

  1. Rule – For a number X and for a number a where a = 1, 2, 3….. do next number = x + a2
  2. E.g. – 5
    • 5 + 2= 5 + 4 = 9
    • 9 + 32 = 9 + 9 = 18
    • 18 + 42 = 18 + 16 = 34
    • 34 + 52 = 34 + 25 = 59
  3. Result – 5, 9, 18, 34, 59 …..

Square up Add up +(Hard to Identify)

  1. Rule – For a number X and for a number a where a = 1, 2, 3….. do next number = x + a+ b for b some pattern.
  2. E.g. – 5
    • 5 + 2+ 3 = 5 + 4 + 3 = 12
    • 12 + 32 + 3 = 12 + 9 + 3 = 24
    • 24 + 42 + 3 = 24 + 16 + 3 = 43
    • 43 + 52 + 3 = 43 + 25 + 3 = 71
  3. Result – 5, 12, 24, 43, 71 …..

Square up Step up +(Very hard to identify not asked mostly unless paper is very tough)

  1. Rule – For a number X and for a number a where a = 1, 2, 3….. do next number = x + katex is not defined + b for b some pattern.
  2. E.g. – 5
    • 5 + katex is not defined + 3 = 5 + 4 + 3 = 12
    • 12 + katex is not defined + 8(3+5) = 12 + 9 + 8 = 29
    • 29 + katex is not defined +13(8+5) = 29 + 16 + 13 = 58
    • 58 + katex is not defined + 18(13+5) = 58 + 25 + 18 = 101
  3. Result – 5, 12, 29, 58, 101 ..

Square up and Square Add Up Series -

Same for Step up Series +, but instead of adding, Subtract.

Examples of Number Series

Example 1: Find the missing number? 99, 121, 143, ___, 187, 199 .

(a) 170
(b) 165
(c) 158
(d) 172
Ans:
(b)
The given series is an AP with first term as 99 and common difference as 22.

Example 2: Find the next term in the series : 51,52,53,55,58,63,____.
(a) 69
(b) 77
(c) 81
(d) 71
Ans:
(d)
Fibonacci series is added to each term.
51 + 0 =51
51 + 1=52
52 + 1=53
53 + 2=55
55 + 3=58
58 + 5=63
63 + 8=71

Example 3: Find the missing terms? 97,122,107,132,__,__.
(a) 117,142
(b) 122,112
(c) 141,131
(d) 121,131
Ans:
(a)
This series is a result of alternate +25 and -15.
97 + 25=122
122 – 15=107
107 + 25=132
132 – 15=117
117 + 25=142
So, the next two terms are 117 and 142.

Example 4: Fill the missing term in the series
100, 92, 86 ,82, 74, 68, 64, 56, 50, __, ___.
(a) 44, 36
(b) 40, 34
(c) 46, 38
(d) 44, 32
Ans:
(c)
The number series are in successive subtraction series of – 8, -6, -4 and then again -8,-6,-4.
So, the next terms after 50 will be 50-4=46 and 46-8=38.

Example 5: Select the missing number from the given responses.
19, 35, 67, 131, 259, 515, ?
(a) 1281
(b) 1291
(c) 1071
(d) 1027
Ans:
(d)
11 × 2 – 3 = 19
19 × 2 – 3 = 35
35 × 2 – 3 = 67
67 × 2 – 3 = 131
131 × 2 – 3 = 259
259 × 2 – 3 = 515
515× 2 – 3 = 1027

The document Important Formulas: Number Series | Quantitative Aptitude for SSC CGL is a part of the SSC CGL Course Quantitative Aptitude for SSC CGL.
All you need of SSC CGL at this link: SSC CGL
Are you preparing for SSC CGL Exam? Then you should check out the best video lectures, notes, free mock test series, crash course and much more provided by EduRev. You also get your detailed analysis and report cards along with 24x7 doubt solving for you to excel in SSC CGL exam. So join EduRev now and revolutionise the way you learn!
Sign up for Free Download App for Free
315 videos|182 docs|185 tests

Up next

315 videos|182 docs|185 tests
Download as PDF

Up next

Explore Courses for SSC CGL exam
Related Searches

mock tests for examination

,

practice quizzes

,

Viva Questions

,

Summary

,

Important Formulas: Number Series | Quantitative Aptitude for SSC CGL

,

video lectures

,

Free

,

Extra Questions

,

Important Formulas: Number Series | Quantitative Aptitude for SSC CGL

,

Previous Year Questions with Solutions

,

Semester Notes

,

Sample Paper

,

ppt

,

Important Formulas: Number Series | Quantitative Aptitude for SSC CGL

,

Objective type Questions

,

pdf

,

shortcuts and tricks

,

study material

,

past year papers

,

MCQs

,

Exam

,

Important questions

;