а) 1 5/6 - 11/12 = 6/6 + 5/6 - 11/12 = 11/6 - 11/12 = (22/12) - (11/12) = 11/12
б) 7/20 + 3/20 = 10/20 = 1/2
в) 25/27 - 7/27 = 18/27 = 2/3
а) 1 5/6 - 11/12 = 6/6 + 5/6 - 11/12 = 11/6 - 11/12 = (22/12) - (11/12) = 11/12
б) 7/20 + 3/20 = 10/20 = 1/2
в) 25/27 - 7/27 = 18/27 = 2/3