19999.9+1999.9+199.9+19.9+1.9怎么巧算
问题描述:
19999.9+1999.9+199.9+19.9+1.9怎么巧算
答
19999.9+1999.9+199.9+19.9+1.9
=20000+2000+200+20+2-0.5
=22221.5