Question

169169ⅹ581－581581ⅹ169用简便方法计算？

Answer 1

169169ⅹ581－581581ⅹ169
=1001x169x581-1001x581x169
=0

Answer 2

169169×581－581581×169
=169×1001×581-581×1001×169
=169×1001×（581-581）
=169×1001×0
=0