9 7/32 + (-8 5/18 - 6 7/12) - (13 5/12 + 7 7/32) =
9 7/32 - 8 5/18 - 6 7/12 - 13 5/12 - 7 7/32 =
(9 7/32 - 7 7/32) - (6 7/12 + 13 5/12) - 8 5/18 =
2 - 20 - 8 5/18 = -18 - 8 5/18 = -26 5/18;
9 7/32 + (-8 5/18 - 6 7/12) - (13 5/12 + 7 7/32) =
9 7/32 - 8 5/18 - 6 7/12 - 13 5/12 - 7 7/32 =
(9 7/32 - 7 7/32) - (6 7/12 + 13 5/12) - 8 5/18 =
2 - 20 - 8 5/18 = -18 - 8 5/18 = -26 5/18;