Кобщему знаменателю дроби: 2/15 и 11/12 1/12 и 1/18 1/24 и 1/18 3/10,3/8 и 3/4 все

НОК(12,15) = 60 и 2/15 = 8/60 и 11/12 = 55/60
НОК(12,18) = 36 и 1/12 = 3/36 и  1/18 = 2/36
НОК(18,24) = 72
НОК(4,8,10) = 40   и 3/10 = 12/40 и 3/8 = 5/40 и 3/4 = 30/40