竖式计算．65×3.12=289.8÷18=（验算）18.5÷39≈（保留两位小数）
口算：= = = == = = =
计算下列题 ．
简算．×4+57×（0.85+0.85+0.85+0.85）×2.5．
能简算就要简算．×+÷1.25×7×0.8 7.28﹣3.14+2.72﹣2.86．
简算：①；②18.76﹣3.47﹣0.53；③36×99．
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