669*670*671-668*670*672=how many.
669*670*671-668*670*672=多少．
<gadget id="calculator">669 * 670 * 671</gadget>
<output>300_762_330</output>

<gadget id="calculator">668 * 670 * 672</gadget>
<output>300_760_320</output>

<gadget id="calculator">300_762_330 - 300_760_320</gadget>
<output>2_010</output>

<result>2_010</result>