4/45 /(12/25 - 4/15) + 15/10 * 4/15 =
12/25 - 4/15 = 36/75 - 20/75 = 16/75
15/10 * 4/15 = 15 * 4 / 15 * 10 = 4/10
(4/ 45) / (16/75) = 4 * 75 / 45 * 16 = 75/45 *4 = 15/9*4
15/36 + 4 / 10 = (150 + 144)/360 = 294/360
