12345679*81=?

12345679*81

=(11111111+1111111+111111+11111+1111+111+11+2)*9*9

=(99999999+9999999+999999+99999+9999+999+99+9+9)*9

=(100000000+10000000+1000000+100000+10000+1000+100+10+10-9)*9

=111111111*9

=999999999

Done.

posted @ 2012-04-22 13:33  Tup  阅读(665)  评论(1编辑  收藏  举报