(1/10 + 3/5) · 15 = 10 целых 1/2
1) 1/10 + 3/5 = 1/10 + 6/10 = 7/10
2) 7/10 · 15/1 = (7·3)/(2·1) = 21/2 = 10 1/2
- - - - - - - - - - - -
12 · (2/3 - 1/4) = 5
1) 2/3 - 1/4 = 8/12 - 3/12 = 5/12
2) 12 · 5/12 = 1 · 5 = 5
- - - - - - - - - - - -
1/10 + 3/5 · 1/4 = 1/4
1) 3/5 · 1/4 = 3/20
2) 1/10 + 3/20 = 2/20 + 3/20 = 5/20 = 1/4
- - - - - - - - - - - -
2 1/2 - 3/5 · 5/6 = 2
1) 3/5 · 5/6 = (1·1)/(1·2) = 1/2
2) 2 1/2 - 1/2 = 2