0,25 * 7 = 1,751/6 : (-3 7/12) = 1/6 : (-43/12) = 1/6 * (-12/43) = -2/435 7/40 + (-1 5/8) = 5 7/40 - 1 5/8 = (5 + 7/40) - (1 + 5/8) = (200/40 + 7/40) - (40/8 + 5/8) = (207/40) - (45/8) = (207/40) - (225/40) = -18/40 = -9/20

Итак, результат вычислений:

1,75-2/43-9/20