计算:(m+3m+5m+…+2013m)-(2m+4m+6m+…+2014m)=(  ) A.-1007m B.-1006m C.-1005m D.-1004m

问题描述:

计算:(m+3m+5m+…+2013m)-(2m+4m+6m+…+2014m)=(  )
A. -1007m
B. -1006m
C. -1005m
D. -1004m

原式=m+3m+5m+…+2013m-2m-4m-6m-…-2014m
=(m-2m)+(3m-4m)+(5m-6m+)…+(2013m-2014m)
=-1007m.
故选A.