Выполните сложение: а) 3/4 + 1/5; б) 1/36 + 5/12; в)

Чтобы выполнить сложение приведем дроби к общему знаменателю:

1) 3/4 + 1/5 = (3 * 5)/(4 * 5) + (1 * 4)/(5 * 4) = 15/20 + 4/20 = (15 + 4)/20 = 19/20;

2) 1/36 + 5/12 = 1/36 + (5 * 3)/(12 * 3) = 1/36 + 15/36 = 16/36 = 4/9;

3) 3/4 + 1/10 = (3 * 5)/20 + (1 * 2)/20 = 15/20 + 2/20 = 17/20;

4) 7/15 + 1/5 = 7/15 + (1 * 3)/15 = 7/15 + 3/15 = 10/15 = 2/3;

5) 1/6 + 7/10 = (1 * 5)/30 + (7 * 3)/30 = 5/30 + 21/30 = 26/30 = 13/15;

6) 1/3 + 1/4 = 4/12 + 3/12 = 7/12;

7) 1/15 + 5/6 = 2/30 + (5 * 5)/30 = 2/30 + 25/30 = 27/30 = 9/10;

8) 1/5 + 5/6 = 6/30 + 25/30 = 31/30 = 1 1/30.