2012*2012-2013*2011=how much.
2012*2012-2013*2011=多少．
<gadget id="calculator">2_012 * 2_012</gadget>
<output>4_048_144</output>

<gadget id="calculator">2_013 * 2_011</gadget>
<output>4_048_143</output>

<gadget id="calculator">4_048_144 - 4_048_143</gadget>
<output>1</output>

<result>1</result>