Improper fraction of 1(2/3) = 1 + 2/3 = 5/3
Improper fraction of 3(8/15) = 3 + 8/15 = 53/15
1(2/3) + 3(8/15) = 5/3 + 53/15
= (5 * 5 + 53) / 15 = 78/15
Convert 78/15 to mixed number = 5 (3/15)