25 целых 3/4 + (-51 целая 1/4) 18 целых 5/6 + (-7 1/2)

а) 25 3/4 + ( - 51 1/4) = 103/4 - 205/4 = - (205 - 103) / 4 = - 102/4 = сократим на 2 = - 51/2 = - 25 1/2.

Преобразуем:

1. 25 3/4 = (25 * 4 + 3) / 4 = 103/4.

2. 51 1/4 = (51 * 4 + 1) / 4 = 205/4.

б) 18 5/6 + ( - 7 1/2) = 113/6 - 15/2 = (113 - 45) / 6 = 68/6 сократим на 2 = 34/3 = 11 1/3.

Преобразуем:

1. 18 5/6 = (18 * 6 + 5) / 6 = 113/6.

2. 7 1/2 = (7 * 2 + 1) / 2 = 15/2.