Ответ:
9
Пошаговое объяснение:
1) 7/15 + 3/10= 7/15*2 + 3/10*3 = 14/30 + 9/30 = 23/30
2)30/57 - 3/19 = 3/19*3= 30/57 - 9/57= 21/57
3) 23/30* 2 14/23 = 23/30 * 60/23 = 1/1 * 3/1 =3/1= 3
4) 1 6/57 : 21/57 = 63/57 : 21/57 = 63/57 * 57/21 = 3/1 * 1/1 = 3/1 - 3
5) 3 + 3 = 9