1)|-9| - |-12|=9-12=-3
2)|-9| + |-12|=9+12=21
3)-9 - (-12)=-9+12=3; |3|=3
4)-9 + (-12)=-9-12=-21; |-21|=21
1)|-9| - |-12|=9-12=-3
2)|-9| + |-12|=9+12=21
3)-9 - (-12)=-9+12=3; |3|=3
4)-9 + (-12)=-9-12=-21; |-21|=21