文本内容:
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=310–120=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=190。