4 5/12 - 1 1/2 : (2 1/6 + 8/15) · 1 4/5 = 3 целых 5/12
1) 2 1/6 + 8/15 = 2 5/30 + 16/30 = 2 21/30 = 2 7/10
2) 1 1/2 : 2 7/10 = 3/2 : 27/10 = 3/2 · 10/27 = (1·5)/(1·9) = 5/9
3) 5/9 · 1 4/5 = 5/9 · 9/5 = 1
4) 4 5/12 - 1 = 3 5/12
