Verified answer

№ 138.

[(58 4/15 - 56 7/24) : 0,8] + [(1 21/40 + 0,225) / (8 3/4 · 3/5)] = 2 77/96

1) 58 4/15 - 56 7/24 = 58 32/120 - 56 35/120 = 57 152/120 - 56 35/120 = 1 117/120 = 1 39/40

2) 1 39/40 : 0,8 = 79/40 : 4/5 = 79/40 · 5/4 = (79·1)/(8·4) = 79/32 = 2 15/32

3) 1 21/40 + 0,225 = 1,525 + 0,225 = 1,75 = 1 3/4

4) 8 3/4 · 3/5 = 35/4 · 3/5 = (7·3)/(4·1) = 21/4

5) 1 3/4 : 21/4 = 7/4 · 4/21 = 7/21 = 1/3

6) 2 15/32 + 1/3 = 2 45/96 + 32/96 = 2 77/96