23/30+2/45=? 27/75+0,32-7/15=? (1/3-1/4) - (1/5-1/6) = ?

Question

Николай Павлов

Математика

18 августа, 09:02

23/30+2/45=? 27/75+0,32-7/15=? (1/3-1/4) - (1/5-1/6) = ?

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Анна Волкова · Answer 1

1. 23/30 + 2/45 = (23 * 3) / 90 + (2 * 2) / (45 * 2) = 69/90 + 4/90 = (69 + 4) / 90 = 73/90.

2. 27/75 + 0,32 - 7/15 = - 11/25.

1) 27/75 + 0,32 = (3 * 9) / (3 * 25) - 32/100 = 9/25 - 32/100 = 9/25 - (4 * 8) / (4 * 25) = 9/25 - 8/25 = 1/25;

2) 1/25 - 7/15 = 3/75 - 35/75 = - 33/75 = - 11/25.

3. (1/3 - 1/4) - (1/5 - 1/6) = 1/20.

1) 1/3 - 1/4 = (1 * 4) / (3 * 4) - (1 * 3) / (4 * 3) = 4/12 - 3/12 = (4 - 3) / 12 = 1/12;

2) 1/5 - 1/6 = 6/30 - 5/30 = (6 - 5) / 30 = 1/30;

3) 1/12 - 1/30 = (1 * 5) / (12 * 5) - (1 * 2) / (30 * 2) = 5/60 - 2/60 = 3/60 = 1/20.