Вычислите 5/6 + 3/8, 9/10+ 3/4 , 3/10+ 2/15, 5/6 - 1/15, 11/12 - 3/8, 5/9 - 1/6

Приведем дроби к общему знаменателю и вычислим:

1) 5/6 + 3/8 = (5 * 4)/(6 * 4) + (3 * 3)/(8 * 3) = 20/24 + 9/24 = (20 + 9)/24 = 29/24 = 1 (29 - 24)/24 = 1 5/24;

2) 9/10 + 3/4 = (9 * 2)/20 + (3 * 5)/20 = 18/20 + 15/20 = (18 + 15)/20 = 33/20 = 1 13/20;

3) 3/10 + 2/15 = (3 * 3)/30 + (2 * 2)/30 = 9/30 + 4/30 = (9 + 4)/30 = 13/30;

4) 5/6 - 1/15 = (5 * 5)/30 - (1 * 2)/30 = 25/30 - 2/30 = (25 - 2)/30 = 23/30;

5) 11/12 - 3/8 = (2 * 11)/24 - (3 * 3)/24 = 22/24 - 9/24 = (22 - 9)/24 = 13/24;

6) 5/9 - 1/6 = (5 * 2)/18 - (1 * 3)/18 = 10/18 - 3/18 = (10 - 3)/18 = 7/18.