4- Resolva as expressões:
a- (40-20) + ( 40+ 20) =
b- (30-15) + 30=
C- (50+5)+( 30-24)=
![4 Resolva As Expressõesa 4020 40 20 B 3015 30C 505 3024 class=](https://pt-static.z-dn.net/files/d58/e8a51e7a3d6fb888eadaf8b82219fad9.jpg)