99x39+39(不用列竖式的简便算法)?

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99x39+39(不用列竖式的简便算法)?

99x39+39(不用列竖式的简便算法)?
99x39+39(不用列竖式的简便算法)?

99x39+39(不用列竖式的简便算法)?
99x39+39
=99x39+39x1
=(99+1)x39
=100x39
=3900

(100-1)x39+39=100x39-1x39+39=3900;
或者,提取1个39,即39x(99+1)=39x100=3900

99x39+39
=99x39+39x1
=(99+1)x39
=100x39
=3900
乘法分配率哦