2+(-4)+6+(-8)+……+46+(-48)+50= -1-3-5-7-9-…-97-99=

问题描述:

2+(-4)+6+(-8)+……+46+(-48)+50= -1-3-5-7-9-…-97-99=

2+(-4)+6+(-8)+……+46+(-48)+50
=-2-2-2-2------+50
=-2*24+50
=-48+50
=2
-1-3-5-7-9-…-97-99=
=(-1-99)+(-3-97)+(-5-95)+-----
=-100*25
=-2500