1. б) Вычислите: 1 1/4 + 5/17 · 4/15 - 2 1/8 : 51/56

1 1/4 + 5/17 · 4/15 - 2 1/8 : 51/56 = 5/4 + 20/255 - 17/8 · 56/51 = 5/4 + 4/51 - 17/8 · 56/51 = 5/4 + 4/51 - (17·56)/(8·51) = 5/4 + 4/51 - (17·7)/(1·51) = 5/4 + 4/51 - 119/51 = 5/4 - 115/51 = (5·51 - 115·4)/(4·51) = (255 - 460)/204 = -205/204 = -1 1/204