人教版几百几十加减几百几十的估算(1).ppt

估 算,电风扇192元,买这两样物品大约一共要多少元呢？,电饭锅319元,电风扇192元,电风扇比电饭锅大约便宜了多少元呢？,电饭锅319元,电风扇192元,老师带500元去买这两样东西够吗？,电饭锅319元,+ =1000,+ =1000,580,★,583+417,1000,,,≈,600,★,估一估，练一练,,,400,420,+ = 910,+ = 900,620,★,619+289,910 900,,,≈,600,★,,,300,290,- =150,- =100,730,★,728-583,150 100,,,≈,700,★,估一估，练一练,,,600,580,- = 190,- = 200,360,★,362-167,190 200,,,≈,400,★,,,200,170,430,+ =640,320,318+321,640,≈,估一估，练一练,,,320,+ = 570,140,136+432,570,≈,,,- =310,690,693-381,310,,,≈,估一估，练一练,380,- = 160,480,482-315,160,,,≈,320,583+419≈,718+179 ≈,做一做,631-409 ≈,529-247 ≈,,,,456 - 197,875 - 463,724 + 131,389 + 122,624 - 147,一共有 237 页，大约 还有 _____ 页没看。

100,142,143,237 - 142,100（页）,240,140,≈,乘火车比乘飞机大约便宜 _____ 元北京到大连，飞机票 620 元，火车票 147 元470,620 - 147,≈ 470 （元）,620,150,。