(2010-1)+(2000-2)+(1999-3)+.+(1002-1000)
问题描述:
(2010-1)+(2000-2)+(1999-3)+.+(1002-1000)
答
原式=(1001+1002+1003+.+2000)-(1+2+3+.+1000)+(2010-1001)
=(1001-1)+(1002-2)+.+(2000-1000)+(2010-1001)
=1000*1000+1009
=1001009