a) 3/5 - 1/4 + 1/3 = 9/15 - 3/15 + 5/15 = 11/15
б) 1/3 - 1/9 + 1/6 = 2/6 - 1/6 + 3/6 = 4/6 = 2/3
в) (2/3 + 1/9) - 13/18 = 6/9 + 1/9 - 13/18 = 7/9 - 13/18 = 14/18 - 13/18 = 1/18
a) 3/5 - 1/4 + 1/3 = 9/15 - 3/15 + 5/15 = 11/15
б) 1/3 - 1/9 + 1/6 = 2/6 - 1/6 + 3/6 = 4/6 = 2/3
в) (2/3 + 1/9) - 13/18 = 6/9 + 1/9 - 13/18 = 7/9 - 13/18 = 14/18 - 13/18 = 1/18