Verified answer

(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

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12 · (2/3 - 1/4) = 5

1) 2/3 - 1/4 = 8/12 - 3/12 = 5/12

2) 12 · 5/12 = 1 · 5 = 5

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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

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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