(1+0.3+0.31+0.32……+0.39)×(0.3+0.31+0.32+……+0.39+0.4)-(1+0.3+
来源:学生作业帮 编辑:百度作业网作业帮 分类:数学作业 时间:2024/08/18 16:34:49
(1+0.3+0.31+0.32……+0.39)×(0.3+0.31+0.32+……+0.39+0.4)-(1+0.3+0.31+0.32……+0.39+0.4)×(0.3+0.31+0.32+……+0.39)=
![(1+0.3+0.31+0.32……+0.39)×(0.3+0.31+0.32+……+0.39+0.4)-(1+0.3+](/uploads/image/z/2955840-24-0.jpg?t=%281%2B0.3%2B0.31%2B0.32%E2%80%A6%E2%80%A6%2B0.39%29%C3%97%280.3%2B0.31%2B0.32%2B%E2%80%A6%E2%80%A6%2B0.39%2B0.4%29-%EF%BC%881%2B0.3%2B)
技巧:巧用乘法分配率.
在式子中+0.4×(0.3+0.31+……+0.39+0.4),再-0.4×(0.3+0.31+……+0.39+0.4)
原式=(1+0.3+0.31+0.32……+0.39)×(0.3+0.31+0.32+……+0.39+0.4)+0.4×(0.3+0.31+……+0.39+0.4)-(1+0.3+0.31+0.32……+0.39+0.4)×(0.3+0.31+0.32+……+0.39)-0.4×(0.3+0.31+……+0.39+0.4)
乘法分配率得
原式=(1+0.3+0.31+0.32……+0.39+0.4)×(0.3+0.31+0.32+……+0.39+0.4)-(1+0.3+0.31+0.32……+0.39+0.4)×(0.3+0.31+0.32+……+0.39)-0.4×(0.3+0.31+……+0.39+0.4)
再次运用乘法分配率得
原式=(1+0.3+0.31+0.32……+0.39+0.4)×0.4-0.4×(0.3+0.31+……+0.39+0.4)
再次运用乘法分配率得
原式=1×0.4
=0.4
希望对你解题有所帮助
在式子中+0.4×(0.3+0.31+……+0.39+0.4),再-0.4×(0.3+0.31+……+0.39+0.4)
原式=(1+0.3+0.31+0.32……+0.39)×(0.3+0.31+0.32+……+0.39+0.4)+0.4×(0.3+0.31+……+0.39+0.4)-(1+0.3+0.31+0.32……+0.39+0.4)×(0.3+0.31+0.32+……+0.39)-0.4×(0.3+0.31+……+0.39+0.4)
乘法分配率得
原式=(1+0.3+0.31+0.32……+0.39+0.4)×(0.3+0.31+0.32+……+0.39+0.4)-(1+0.3+0.31+0.32……+0.39+0.4)×(0.3+0.31+0.32+……+0.39)-0.4×(0.3+0.31+……+0.39+0.4)
再次运用乘法分配率得
原式=(1+0.3+0.31+0.32……+0.39+0.4)×0.4-0.4×(0.3+0.31+……+0.39+0.4)
再次运用乘法分配率得
原式=1×0.4
=0.4
希望对你解题有所帮助
(1+0.3+0.31+0.32……+0.39)×(0.3+0.31+0.32+……+0.39+0.4)-(1+0.3+
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