2/5 : 7/10 + 2 1/3 · 2/7 = 1 5/21
1) 2/5 : 7/10 = 2/5 · 10/7 = (2·2)/(1·7) = 4/7
2) 2 1/3 · 2/7 = 7/3 · 2/7 = 2/3
3) 4/7 + 2/3 = 12/21 + 14/21 = 26/21 = 1 5/21
ответ: 1 целая 5/21.
