Завдання 501 - 600 » 515

Обчисліть: 1) 7/9 : 21/3 = 7/9 : 7/3 = 7/9 ∙ 3/7 = 1/3; 2) 11/19 : 120/57 = 11/19 : 77/57 = 11/19 ∙ 57/77 = 3/7; 3) 31/5 : 24/35 = 16/5 ∙ 35/24 = 14/3 = 42/3; 4) 4 : 15/11 = 4 : 16/11 = 4 ∙ 11/16 = 11/4 = 23/4.