1.9加19.9加199.9加1999.9加0.4怎样算简便就怎样算?

2024-11-22 00:51:02
推荐回答(3个)
回答(1):

1.9+19.9+199.9+1999.9+0.4
=2-0.1+20-0.1+200-0.1+2000-0.1+0.4
=(2+20+200+2000)-(0.1×4-0.4)
=2222

回答(2):

把0.4拆成四个0.1=2+20+200+2000=2222

回答(3):

=(2-O.1)十(20-O.1)十(200一O.1)十(2000-O.1)十0.4 =2十20十200十2000 =2222