2012+2011-2010-2009+2008+2007-2006-2005+2004+...+7-6-5+4+3-2-1=how much.
2012+2011-2010-2009+2008+2007-2006-2005+2004+…+7-6-5+4+3-2-1=多少．
<gadget id="calculator">2_012 / 4</gadget>
<output>503</output>

<gadget id="calculator">4 * 503</gadget>
<output>2_012</output>

<result>2_012</result>