a) 7/2-5/9 - 63/18-10/18=53/18=2и17/18
б) 5/4-1/3=15/12-4/12=11/12
в) 28/15-2/5=28/15-6/15=22/15=1и7/15
г) 4/3-5/6=8/6-5/6=3/6=1/2
д) 3и9/25 - 1и9/10 = 2 и(18/50-45/50)= 1 и (68/50-45/50)= 1и 23/50 = 1,46;
е) 16 и 2/15-122/15 = 4и(6/15-10/15)= 3 и (81/75-10/75) = 3и71/75