15. Сократите дроби.

а) 2/4 = 1/2, 6/10 = 3/5, 3/9 = 1/3, 6/15 = 2/5. б) 12/16 = 3/4, 20/24 = 5/6, 24/36 = 2/3, 32/40 = 4/5. в) 28/36 = 7/9, 28/56 = 1/2, 48/60 = 4/5, 40/84 = 10/21. г) 48/72 = 2/3, 60/96 = 5/8, 72/90 = 4/5, 60/100 = 3/5.