Answer: 7 13/15
Explanation:
First of, you have to get your common denominator, as it's impossible without one.
The closest common denominator is 15, and it will ask you for a simplified version.
Multiply the 2/3 in 5 2/3 by 5 on both sides to get 5 10/15
Multiply the 1/5 in 2 1/5 by 3 on both sides to get 2 3/15
Then add up your sum.
5 10/15+2 3/15=7 13/15