1.输出值为2×(-2)+4=0
2.9又7/8×3=(10-1/8)×3=10×3-1/8×3.使用了乘法分配律,选择D
3.原式=1+2+3+...+32-(3+6+9+...+99)
=17×33-33-3×(1+2+3+...+33)
=16×33-3×17×33
=33×(-35)
=-1155
4.-1/n×1/(n+1)=-1/n+1/(n+1)
运用规律:原式=-1+1/2-1/2+1/3-1/3+1/4-...-1/2008+1/2009
=-1+1/2009
=-2008/2009