Завдання 401 - 500 » 498

Обчисліть: 1) 2/5 : 2/15 = 2/5 ∙ 15/2 = 3; 2) 3/4 : 3/12 = 3/4 ∙ 12/3 = 3; 3) 4/7 : 4/21 = 4/7 ∙ 21/4 = 3; 4) 13/15 : 13/45 = 13/15 ∙ 45/13 = 3; 5) 2/5 : 6/25 = 2/5 ∙ 25/6 = 5/3 = 12/3; 6) 3/4 : 7/12 = 3/4 ∙ 12/7 = 9/7 = 12/7; 7) 11/12 : 11/18 = 11/12 ∙ 18/11 = 3/2 = 11/2; 8) 13/15 : 26/27 = 13/15 ∙ 27/26 = 9/10; 9) 2/7 : 8/21 = 2/7 ∙ 21/8 = 3/4; 10) 5/24 : 15/64 = 5/24 ∙ 64/15 = 8/9; 11) 33/81 : 11/45 = 33/81 ∙ 45/11 = 15/9 = 12/3; 12) 15/38 : 5/19 = 15/38 ∙ 19/5 = 3/2 = 11/2.