2 · 1 5/12 + 4 · 1 1/8 + 1 1/9 · 1 1/4 = 8 13/18
1) 2 · 1 5/12 = 2 · 17/12 = 17/6 = 2 5/6
2) 4 · 1 1/8 = 4 · 9/8 = 9/2 = 4 1/2
3) 1 1/9 · 1 1/4 = 10/9 · 5/4 = (5·5)/(9·2) = 25/18 = 1 7/18
4) 2 5/6 + 4 1/2 = 2 5/6 + 4 3/6 = 6 8/6 = 6 4/3 = 7 1/3
5) 7 1/3 + 1 7/18 = 7 6/18 + 1 7/18 = 8 13/18
ответ: 8 целых 13/18.
