1. 1*(-7)-1= 2. 12*(-7)-2= 3. 123*(-7)-3= 4. 9*(-9)+1= 5. 98*(-9)+2= 6. 987*(-9)+3=

问题描述:

1. 1*(-7)-1= 2. 12*(-7)-2= 3. 123*(-7)-3= 4. 9*(-9)+1= 5. 98*(-9)+2= 6. 987*(-9)+3=

1.1*(-7)-1
=-7-1
=-8
2.12*(-7)-2
=-84-2
=-86
3.123*(-7)-3
=-861-3
=-864
4.9*(-9)+1
=-81+1
=-80
5.98*(-9)+2
=-882+2
=-880
6.987*(-9)+3
=-8883+3
=-8880