9+99+999+9999+99999 = =
问题描述:
9+99+999+9999+99999 = =
答
9+99+999+9999+99999
=(10-1)+(100-1)+(1000-1)+(10000-1)+(10000-1)
=10+100+1000+10000+100000-5
=111110-5
=111105