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            【小学数学解题思路大全】式题的巧解妙算?(五)

            2009-04-30  mishoushu

            22.以乘代除

              例如,2.7÷4÷6×24÷27

                

            23.以除代除

              

              观察其特点,

              

            24.并数凑整

              例如,372+499

              =372+500-1=871

              56.7-12.8

              =56.7-13+0.2=43.9

            25.拆数凑整

              例如,476+302

              =476+300+2=778

              9.42-3.1

              =9.42-3-0.1=6.32

            26.加分数凑整

              应用“被减数、减数同时增加或减少相同的数,其差不变”的性质,使原来减去一个带分数或带小数,变成减去整数。

              

              

              例3 8.37-5.68

               =(8.37+0.32)-(5.68+0.32)

               =8.69-6=2.69

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