а) 3/4 + 1/5; = 15/20 + 4/20 = 19/20
б) 1/36 + 5/12; = 1/36 + 15/36 = 16/36 = 4/9
в) 3/4 + 1/10; = 15/20 + 2/20 = 17/20
7/15+1/5 ; = 75/5 + 1/5 = 76/5 = 15
1/6+7/10; = 5/30 + 21/30 = 26/30 = 13/15
1/3 +1/4 ; = 4/12 + 3/12 = 7/12
1/15+5/6 ; = 2/30 + 25/30 = 27/30 = 9/10
1/5+56 = 1/5 + 280/5 = 281/5 = 56 2/10