Выполнить деянья с дробями:9/56-(7/15-5/12)*(3/14+1/2) и (2/3+7/8-5/6)* (1-5/17)

А) 9/56 - (7/15 - 5/12) * (3/14 + 1/2) = 1/8 = 0,125;

1). 7/15 - 5/12 = 28/60 - 25/60 = (28 - 25)/60 = 3/60 = 1/20;

2). 3/14 + 1/2 = 3/14 + 7/14 = (3 + 7)/14 = 10/14 = 5/7;

3). 1/20 * 5/7 = 1 * 5/20 * 7 = 1 * 1/4 * 7 = 1/28;

4). 9/56 - 1/28 = 9/56 - 2/56 = (9 - 2)/56 = 7/56 = 1/8 = 0,125;

Б) (2/3 + 7/8 - 5/6) * (1-5/17) = 1/2 = 0,5;

1). 2/3 + 7/8 = 16/24 + 21/24  (16 + 21)/24 = 37/24 = 1 13/24;

2). 1 13/24 - 5/6 = 37/24 - 5/6 = 37/24 - 20/24 = (37 - 20)/24 = 17/24;

3). 1 - 5/17 = 17/17 - 5/17 = (17 - 5)/17 = 12/17;

4). 17/24 * 12/17 = 17 * 12/24 * 17 = 1 * 1/2 * 1 = 1/2 = 0,5;