Simple calculation: 2015*21062016-2016*20152015.
简便计算：2015*21062016-2016*20152015．
<gadget id="calculator">2_015 * 2_016 * 10_001</gadget>
<output>40_626_462_240</output>

<gadget id="calculator">2_016 * 2_015 * 10_001</gadget>
<output>40_626_462_240</output>

<gadget id="calculator">40_626_462_240 - 40_626_462_240</gadget>
<output>0</output>

<result>0</result>