№ 546.
а) 1 7/15 + 2 3/15 - 1 8/15 - 1 4/15 = (1 + 2 - 1 - 1) + (7/15 + 3/15 - 8/15 - 4/15) = 1 + (-2/15) = 15/15 - 2/15 = 13/15;
б) 3 12/13 - 1 5/13 - 1 9/13 + 2 3/13 = (3 - 1 - 1 + 2) + (12/13 - 5/13 - 9/13 + 3/13) = 3 + 1/13 = 3 1/13;
в) 3 2/17 + 1 12/17 + 2 3/17 - 3 8/17 = (3 + 1 + 2 - 3) + (2/17 + 12/17 + 3/17 - 8/17) = 3 + 9/17 = 3 9/17;
г) 5 3/14 - 1 5/14 + 2 9/14 - 4 13/14 = (5 - 1 + 2 - 4) + (3/14 - 5/14 + 9/14 - 13/14) = 2 + (-6/14) = 1 14/14 - 6/14 = 1 8/14 = 1 4/7.