答:原式=199.8+0.2+19.98+0.02+1.998+0.002+2=224
(199.8+0.2)+(19.98+0.02)+(1.998+0.002)+2=200+20+2+2=224
199.8+19.98+1.998+2.222
=199.8+19.98+1.998+(2+0.2+0.02+0.002)
=(199.8+0.2)+(19.98+0.02)+(1.998+0.002)+2
=224
199.8与200差0.2
19.88与20差0.02
1.998与2差0.002
所以答案为200+20+2+2=224(2.222拆分成2、0.2、0.02、0.002)
希望采纳