B-1: 1 + 5/6 + 7/8 - 1 - 11/21 - 3 - 33/35.

1 + 5/6 + 7/8 - 1 - 11/21 - 3 - 33/35 = (1 - 1 - 3) + (5/6 + 7/8 - 11/21 - 33/35) = -3 + (140/168 + 147/168 - 88/84 - 165/175) = -3 + (287/168 - 11/21 - 33/35) = -3 + (287/168 - 88/84 - 165/175) = -3 + (287/168 - 176/168 - 165/175) = -3 + (111/168 - 165/175) = -3 + (37/56 - 33/35) = -3 + (185/280 - 264/280) = -3 - 79/280 = -3 - 0.282 = -3.282