Розвязати 4/27-1/6+7/18
4/27 - 1/6 + 7/18 = 8/54 - 9/54 + 21/54 = (8 - 9 + 21)/54 = 20/54 = 10/27
4/27-1/6+7/8=8/54-9/54+21/54=-1/54+21/54=20/54=10/27