2010+2009-2008-2007+...-4-3+2+1.
2010+2009-2008-2007+…-4-3+2+1．
<gadget id="calculator">4 * 502</gadget>
<output>2_008</output>

<gadget id="calculator">2_008 + 3</gadget>
<output>2_011</output>

<result>2_011</result>