А) (5/6-2/3):8/9 Б)2/3:(2/5+4/15) В) 10:2/5-3/10 Г) (1 1/2+3/8):3 А)(1-1/2): (1/2-1/3) А)

Вычислим значения выражений:

А) (5/6 - 2/3) : 8/9 = (5/6 - 4/6) : 8/9 = 1/6 : 8/9 = 1/6 * 9/8 = 3/2 * 8 = 3 * 4 = 12; 

Б) 2/3 : (2/5 + 4/15) = 2/3  : (2 * 3 + 4)/15 = 2/3 : 10/15 = 2/3 * 15/10 = 2/3 * 3/2 = 1; 

В) 10 : 2/5 - 3/10 = 10 * 5/2 - 3/10 = 25 - 3/10 = 24 7/10; 

Г) (1 1/2 + 3/8) : 3 = (3/2 + 3/8) : 3 = 3/2 * 1/3 + 3/8 * 1/3 = 1/2 + 1/8 = 4/8 + 1/8 = 5/8; 

А) (1 - 1/2) : (1/2 - 1/3) = 1/2 : (3/6 - 2/6) = 1/2 : 1/6 = 1/2 * 6/1 = 6/2 = 3; 

А) (3/4 + 1/6) * 3 + (5/6 - 1/2) : 2/9 = (3 * 3 + 1 * 2)/12 * 3+ (5 - 1 * 3)/6 : 2/9 = 11/4  + 1/6 * 9/2 = 11/4 + 1/3 * 3/2 = 11/4 + 1/2 = 11/4 + 2/4 = 15/4 = 3 3/4; 

Б) (1 1/5 + 2 3/10) : 1/2 + (6 3/4 - 2 2/3) : 1 1/6 = (3 + 5/10) : 1/2 + (4 + 3/4 - 2/3) : 7/6 = 7/2 * 2/1 + (4 + (9 - 8)/12) * 6/7 = 7 + 4 1/12 * 6/7 = 7 + 49/12 * 6/7 = 7 + 7 * 1/2 = 7 + 3,5 = 10,5.