а) 1/6 + 2/3 = 1/6 + 4/6 = 5/6б) -1/3 + 2/7 = -7/21 + 6/21 = -1/21в) -4/9 + 5/6 = -8/18 + 15/18 = 7/18
а) 1/6 + 2/3 = 1/6 + 4/6 = 5/6
б) -1/3 + 2/7 = -7/21 + 6/21 = -1/21
в) -4/9 + 5/6 = -8/18 + 15/18 = 7/18