1 3/4 - 7/8 - (4/9 + 1/18) - 5/10 = 1 3/4 - 7/8 - (8/18 + 1/18) - 5/10 = 1 3/4 - 7/8 - 9/18 - 1/2 = 1 3/4 - 7/8 - 1/2 - 1/2 = 7/8 - 7/8 - 2/2 = -1.