Question

what should be added to (1/2 + 1/3 - 1/5 ) to get 3 ?

Answer 1

Let the required number be x

A/q,
1/2+1/3-1/5+x=3
(15+10-6)/30+x=3
19/30+x=3
x=3-19/30
x=(90-19)/30
x=71/30

Answer 2

71/30 is your answer to get 3