45x28 72x45简便运算

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图脊没答樱慧察闷

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45x28 72x45简尘虚备誉雀便运算派毁
45x28
=45*20+45*8
=900+360
=1260
72x45
=70*45+2*45
=3150+90
=3240

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45×28+72×45
=45×(28+72)
=45×100
=4500

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45×28+72×45
=45×(28+72)
=45×100
=4500

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