Find a common denominator

2/3+4/5

the CD is 15 because 3 and 5 both go into them.

find how many time the bottom part of the first fraction can go into there.

in this case, 3 can go into 15, 5 times

so then youll mutiple your top number by 5

repeat this for the next fraction

Once you have your four fractions, subtract the top of the two new fractions

in this case it'll be 10 and 12

=2

then put that over 15

=2/15