1、7.2几百几十加减几百几十笔算笔算下列各题：320+ 210 =560 + 110 =250+ 220 =370 + 120 =840+ 160 =770 + 240 =480+ 230 =330 + 390 =450+ 470 =390 + 250 =550+ 390 =190 + 250 =360+250 =440 + 180 =780 250 =360 120 =440 130 =660 250 =360 270 =710 230 =420 130 =370 280 =250 160 =520 140 =960 580 =630 250 =760 290 =550 290 =1310 1
2、20=440 -250 =答案：320+ 210 = 530560 + 110 =670250+ 220 =470370 + 120 =490840+ 160 =1000770 + 240 =1100480+ 230 =710330 + 390 =720450+ 470 =920390 + 250 =640550+ 390 =940190 + 250 =440360+250 =610440 + 180 =620780 250 =530360 120 =240440 130 =310660 250 =410360 270 =90710 230 =480420 130 =290370 280 =90250 160 =90520 140 =380960 580 =360630 250 =380760 290 =470550 290 =260310 120 =190440 -250 =1902
