+(5+7)=5+7

+(3-8+7)=3-8+7

+(-3+8+7)=-3+8+7

+(-10-12+1)=-10-12+1

-(5+7)= -5+7

-(3-8+7)= -3+8+7

-(-3+8+7)= -3-8-7

-(-10-12+1)= -10+12-1

+(56+42)=56+42
+(7×8+42)=7×8+42

-(45-35)=45-35-()
-(45-7×5)=45-7×5
-(45-53)=45-53
-(9×5-53)=9×5-53

+(48-93)-8=48-93-8
-(96-35)-6=96-35-6
-(2×5+48)+7×8=7×8-20+7×8
+(99-5+8)-17=99-5+8-17

-(2×5+48)+23=2×5+48+23
-(32-74)-74=32-74-74
+(-120-9×9)-81=120-9×9-81
+(120-9)+81=120-9+81