Для сравнения дробей надо привести их к общему знаменателю.3/8 и 1/6 --- общий знаменатель 249/24 и 4/24 ----- 9/24 > 4/243/8 > 1/6 --------------------------------------------5/8 и 7/10 ---- общ. знам. = 4025/40 и 28/40 ----- 25/40 < 28/405/8 < 7/10-------------------------------------------3/7 и 9/21 ---- общ.знам. = 219/21 = 9/213/7 = 9/21----------------------------------------3/5 и 5/8 -----общ.знам. = 4024/40 и 25/40 ----24/40 < 25/403/5 < 5/8------------------------------------------7/12 и 11/18 ------общ.знам. = 3621/36 и 22/36----21/36< 22/367/12 < 11/18----------------------------------------10/21 и 9/14 ----общ.знам. = 4220/42 и 27/42 ---- 20/42 < 27/4210/21 < 9/14