Ответ:

Пошаговое объяснение:

№1.

4 2/7 +2 3/7 - 3 4/7= 6 5/7 - 3 4/7 = 3 1/7

11-(2 5/9+3 2/9)= 11 - 5 7/9 = 5 2/9

7 6/23-(3 5\23 +1 11/23)= 7 6/23 - 4 16/23 = 6 29/23 - 4 16/23 = 2 13/23

№2.  

X+15 17/18=22 5/18

x = 22 5/18 - 15 17/18

x = 21 23/18 - 15 17/18

x = 6 6/18

x = 6 1/3

37 4/15+(2 7/15-y)=38 2/15

2 7/15 - y = 38 2/15 - 37 4/15

2 7/15 - y = 13/15

y = 2 7/15 - 13/15

y = 1 9/15

y = 1 3/5

№3.

215м.=? ч.  

1257ме.=? км.  

№4.

3 1/3<a/3<5

a=11;12;13;14