How to add fractions

 

A: Firstly to add fractions the denominators have to be the same.

For example, 3/7 + 2/3

firstly you need to work out the lcm of 7 and 3, in this case it is 21.

So each fraction needs to be put into the form a/21 + b/21

For the fraction 3/7, you are timsing the 7 by 3  to get 21, so you also need to times the numerator by 3 leaving you with 9/21 which = 3/7 

Then starting with 2/3, to get a denominator of 21, you need to times 3 by 7, so you also need to times the numerator by 7 leaving you with 14/21 which =2/3

Finally to add the 2 fractions 9/21 + 14/21 = 23/21

Other examples for you to try..

1) 3/5 + 2/3

2) 3/5 + 6/20

 

JL

Related Maths GCSE answers

All answers ▸

We have the following fractions: 6/16, 9/24, 12/32 and 15/35. Which fraction is not equivalent to 3/8?


How would you prepare for your Maths exam?


Solve the simultaneous equations: y = 4x^2 - 9x - 1 and y = 5 - 4x


Solve the following equation: 7x + 6 = -5x - 42