Дроби к наименьшему общему знаменателю : 7/20 и 5/12 , 11/24 и 1/30 , 3/10 и 7 /16 , 3/16 и 1/10 , 11/18 и 7/12 , 7/24 и 2/15 , 1/12 и 2/9 , 4/21 и 13/28 , 3/14 и 2/21

7/20 и 5/12 = 21/60 и 25/60
11/24  1/30 = 55/120  4/120
3/10 и 7/16 = 24/80 и 35/80
3/16 и 1/10 = 15/80 и 8/80
11/18 и 7/12 = 22/36 и 21/36
7/24 и 2/15 = 35/120 и 16/120
1/12 и 2/9 = 3/36 и 8/36
4/21 и 13/28 = 16/84 и 39/84
3/14 и 2/21 = 18/84 и 8/84