Answer:
21 16/45
Explanation:
12 8/9 - 7 + 7/15 +15
concert mixed numbers to improper fractions
12 8/9 = 12 * 9 + 8 /9 so 116/9
add and subtract (left to right)
116/9 -7 = -7*9 /9 + 116/9
-7*9+116=53 so 53/9
53/9 + 7/15 = 286/45
286/45 + 15 = 961/45
convert improper fractions to mixed numbers
961/45 =21 remainder 16 so
21 16/45 is the answer