Answer :
To add them, you first need a common denominator.
So multiply 1/4 by 5/5 and 1/5 by 4/4 first.
Now they'll be 5/20 and 4/20.
Add them to get 9/20.
So multiply 1/4 by 5/5 and 1/5 by 4/4 first.
Now they'll be 5/20 and 4/20.
Add them to get 9/20.