1 7\8 + ( - 2 3\4) =
1 7\8 - 2 3/4
1 7\8 - 2 6/8
-1 1/8
1 7/8 + (-2 3/4) = 1 7/8 - 2 3/4 = 15/8 - 11/4 = 15/8 - 22/8 = -7/8