2 целых 11/18 + 1 целая 5/9 - (2целых 1/4 - 7/12) = ? пожалуйста, помогите

2 целых 11/18 + 1 целая 5/9 - (2целых 1/4 - 7/12) = 2 1 /2 .1) 2 1 /4 - 7/ 12 = 2 + 1/ 4 - 7/ 12 = 2 - 1·3 /4·3 - 7·1 /12·1 = 2 + 3/ 12 - 7 /12 = 2 + 3 - 7 /12 = 2 - 4 /12 = 2·12/ 12 - 4 /12 = 20 /12 = 5·4/ 3·4 = 5 /3 = 2 + 1·3/ 3 = 1 2 /3 .2) 2 11 /18 + 1 5/ 9 = 3 + 11 /18 + 5/ 9 = 3 + 11·1 /18·1 + 5·2/ 9·2 = 3 + 11/ 18 + 10/ 18 = 3 + 11 + 10/ 18 = 3 21/ 18 = 3 7·3 /6·3 = 3 7 /6 = 3 1 + 1·6 /6 = 4 1/ 6 .3)4 1 /6 - 1 2/ 3 = 3 + 1/ 6 - 2 /3 = 3 - 1·1/ 6·1 - 2·2/ 3·2 = 3 + 1/ 6 - 4/ 6 = 3 + 1 - 4 /6 = 3 - 3/ 6 = 3·6/ 6 - 3/ 6 = 15/ 6 = 5·3 /2·3 = 5/ 2 = 1 + 2·2 /2 = 2 1 /2 .