(3 1/4 + 2 1/6) : 2 3/5 - 2/3 : 4/9 = 7/12
1) 3 1/4 + 2 1/6 = 3 3/12 + 2 2/12 = 5 5/12
2) 5 5/12 : 2 3/5 = 65/12 : 13/5 = 65/12 · 5/13 = (5·5)/(12·1) = 25/12 = 2 1/12
3) 2/3 : 4/9 = 2/3 · 9/4 = (1·3)/(1·2) = 3/2 = 1 1/2
4) 2 1/12 - 1 1/2 = 1 13/12 - 1 6/12 = 7/12
ответ: 7/12.
