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用简便方法计算．0.3×2.5×0.40.78×1012.5×（8＋0.4）1.25×0.7×0.89.8×2.550.8×101－50.84.6×99＋4.60.25×32×0.125

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用简便方法计算．

0.3×2.5×0.4

0.78×101
2.5×（8+0.4）1.25×0.7×0.8
9.8×2.550.8×101-50.8
4.6×99+4.60.25×32×0.125
38.2×8+61.8×8．

热搜：m20螺距为2.5牙深是多少

答案解析

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  • ①0.3×2.5×0.4
    =0.3×（2.5×0.4）
    =0.3×1
    =0.3；②0.78×101
    =0.78×（100+1）
    =0.78×100+0.78
    =78+0.78
    =78.78；③2.5×（8+0.4）
    =2.5×8+2.5×0.4
    =20+1
    =21；④1.25×0.7×0.8
    =（1.25×0.8）×0.7
    =1×0.7
    =0.7；⑤9.8×2.5
    =（10-0.2）×2.5
    =10×2.5-0.2×2.5
    =25-0.5
    =24.5；⑥50.8×101-50.8
    =50.8×（101-1）
    =50.8×100
    =5080；⑦4.6×99+4.6
    =4.6×（99+1）
    =4.6×100
    =460；⑧0.25×32×0.125
    =0.25×4×8×0.125
    =（0.25×4）×（8×0.125）
    =1×1
    =1；⑨38.2×8+61.8×8
    =（38.2+61.8）×8
    =100×8
    =800．