1-3+5-7+9-11+.-1999+2001=?_数学解答

1-3+5-7+9-11+.-1999+2001=?

人气：359 ℃　时间：2020-09-16 14:48:26

解答

1-3+5-7+9-11+.-1999+2001
=(1-3)+(5-7)+...(1997-1999)+2001
=-2-2...-2(共500个）+2001
=-2*500+2001
=1001