3 целых 1/5 + 1 целая 3/5 2 цел.4/9 - 1цел.7/9 1цел.5/7+6/7

1) 3 1/5 + 1 3/5 = (3 * 5 + 1)/5 + (1 * 5 + 3)/5 = (15 + 1)/5 + (5 + 3)/5 = 16/5 + 8/5 = (16 + 8)/5 = 24/5;

Ответ: 24/5.

2) 2 4/9 - 1 7/9 = (2 * 9 + 4)/9 - (1 * 9 + 7)/9 = (18 + 4)/9 - (9 + 7)/9 = 22/9 - 16/9 = (22 - 16)/9 = 6/9 = 2/3;

Ответ: 2/3.

3) 1 5/7 + 6/7 = (1 * 7 + 5)/7 + 6/7 = 12/7 + 6/7 = 18/7;

Ответ: 18/7.