Пошаговое объясне4/45: (12/25 — 4/15) + 15/16 * 4/15 = 2/3
1) 12/25 — 4/15 = 36/75 — 20/75 = 16/75
2) 4/45: 16/75 = 4/45 * 75/16 = (1*5)(3*4) = 5/12
3) 15/16 * 4/15 = 4/16 = 1/4
4) 5/12 + 1/4 = 5/12 + 3/12 = 8/12 = 2/3
