a) 5/7 - 2/5 = (25/35) - (14/35) = 11/35
б) 1/8 + 3/6 = (3/24) + (16/24) = 19/24
в) 11/12 - (2/3 + 1/4) = 11/12 - (8/12 + 3/12) = 11/12 - 11/12 = 0
a) 5/7 - 2/5 = (25/35) - (14/35) = 11/35
б) 1/8 + 3/6 = (3/24) + (16/24) = 19/24
в) 11/12 - (2/3 + 1/4) = 11/12 - (8/12 + 3/12) = 11/12 - 11/12 = 0