2009*2009-2011*2007．
2009*2009-2011*2007．
<gadget id="calculator">2_009 * 2_009</gadget>
<output>4_036_081</output>

<gadget id="calculator">2_011 * 2_007</gadget>
<output>4_036_077</output>

<gadget id="calculator">4_036_081 - 4_036_077</gadget>
<output>4</output>

<result>4</result>