а) 1 4/5 - 9/10 = 9/5 - 9/10 = 18/10 - 9/10 = 9/10
б) 7/24 + 5/24 = 12/24 = 1/2
в) 17/18 - 5/18 = 12/18 = 2/3
а) 1 4/5 - 9/10 = 9/5 - 9/10 = 18/10 - 9/10 = 9/10
б) 7/24 + 5/24 = 12/24 = 1/2
в) 17/18 - 5/18 = 12/18 = 2/3