Let’s take some examples

 

Add 1/3 & 4/3

 

  1/3  + 4/3

Since denominator is same,

  we add numerators

  = (1+ 4)/3

  = 5/3

 

Subtract 6/9 from 2/9

 

  2/9  − 6/9

Since denominator is same,

  we add numerators

  = (2  - 6)/9

  = (-4)/9

 

Subtract 1/2 & 1/5

 

 1/2 − 1/5

= (1 × 5 - 1 × 2)/(2 × 5)

= (5 - 2)/6

= 3/10

 

Add 1/2 & 1/3

 

 1/2 + 1/3

= (1 × 3 + 1 × 2)/(2 × 3)

= (3 + 2)/6

= 5/6

 

Add 1/2 & (-1)/3

 

 1/2 + ((-1)/3)

= 1/2 – 1/3

= (1 × 3 - 1 × 2)/(2 × 3)

= (3 - 2)/6

= 1/6

 

Add (-1)/2 & 1/3

 

 (-1)/2 + 1/3

= (-1 × 3 + 1 × 2)/(2 × 3)

= (-3 + 2)/6

= (-1)/6

 

Add (-1)/2 & (-1)/3

 

 (-1)/2 + ((-1)/3)

= (-1)/2 – 1/3

= (-1 × 3 - 1 × 2)/(2 × 3)

= (-3 - 2)/6

= (-(3 + 2))/6

= (-5)/6

  1. Chapter 9 Class 7 Rational Numbers
  2. Concept wise
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Davneet Singh
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 8 years. He provides courses for Maths and Science at Teachoo. You can check his NCERT Solutions from Class 6 to 12.