绘制数据三角形，研究乘法的规律发现：乘积的最后三位的值只与乘数与被乘数的后三位有关，与乘数和被乘数的高位无关-Plot law triangles, multiplication study found that: the value of the product of the last three and only after about three multiplier and multiplicand nothing to do with high multiplier and multi