Ответ:

Пошаговое объяснение:

1 ) 5 + 2/3 * ( - 2 1/2) = 5 - 2/3 * 5/2 = 5 - 5/3 = 5 - 1 2/3 = 3 1/3

2) - 2 : 5 1/3 - 7/10 : 1 1/15 = -2 : 16/3 - 7/10 : 16/15 = - 2 * 3/16 - 7/10 * 15/16 =

= - 3/8 - 21/32 = - 12/32 - 21/32 = - 33 /32 = - 1 1/32

3) 2 1/5 * 1/3 + (-3/10) : 4 1/2 = 11/5 * 1/3 +(- 3/10 ) : 9/2 =

= 11/15 - 3/10 * 2/9 = 11/15 - 1/15 = 10/15 = 2/3

4) 3/7 - (1 1/4 - 1 1/8 * 2/9)= 3/7 - (5/4 - 9/8 * 2/9) = 3/7 - ( 5/4 - 1/4) =

= 3/7 - 1 = - 4/7