Adding & Subtracting Rational Numbers

Last updated at April 16, 2024 by

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

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science and Computer Science at Teachoo