竖式计算.290+197=验算: 468+398=验算: 4006﹣3749=验算: 1040×9=276×8= 60÷7= 74÷9=
83×26+83×74.
脱式计算,能简算的要简算. 2.79×4.64+2.79×4.36+2.7945.45÷9÷5+﹣+.
415﹣176﹣24.
脱式计算(能简算的要简算) 2.5×1.2+0.25×281.9+19.9+199.9+0.3.
用简便方法计算下面各题. (1)1500﹣28﹣272 (2)99×48+48 (3)2000÷125÷8 (4)77+2.14+23+7.86.