Answer:
Explanation:
Those are fractions, are they not? I'll treat them that way.

Find the lowest common denominator.
You need 1 three and 1 five.
2/5 = (2*3)/(5 * 3) = 6 / 15
2/3 = (2*5)/(3*5) = 10 /15

Just add the numerators.
It is reduced. There are other ways to write it
16/15 = 1 1/15 is one of them