Question

The number of minutes Sadie spends on homework, playing outside, and practicing

piano are known. How much more time Sadie spends on homework, h, is unknown.
90 = (20 + 15) +h

Answer 1

h = 55

Explanation:

90 = (20 + 15) +h

90 = 35 + h

90 - 35 = h

h = 55

Answer 2

h = 55. 35 + 55 = 90