1.21-(5-8)=21-(-3)=24
2.3.7-(4-5.3)=2.7-(-1.3)=4
3.1\6-(5\12-7\12)=2\12-(-2\12)=0
4.-13-(20-32)=-13-(-12)=-1
5.-4.5-(7-9.5)=-4.5-(-2.5)=-2
6.-5\8-(5\8-1)=-5\8-(-3\8)=-2\8
7.-18-(9-5)=-18-4=-22
8.-0.25-(3-2.25)=-0.25-0.75=-1
9.-2\9-(1-8\9)=-2\9-1\9=-3\9=-1\3