1998+199.8+19.98+1.98+2.222计算过程怎么算

1998+199.8+19.98+1.98+2.222计算过程怎么算
1998+199.8+19.98+1.98+2.222计算过程怎么算

1998+199.8+19.98+1.98+2.222计算过程怎么算
将2.222写成2+0.2+0.02+0.002,然后
原式=1998+2+199.8+0.2+19.98+0.02+1.998+0.002
=2000+200+20+2
=2222

先加一个1.998和2.222加，依次往上加1.98,19.98……最后再减1.998