Calculation: (1+2+3+...+2009+2010+2009+...+2+1)/2010.
计算：(1+2+3+…+2009+2010+2009+…+2+1)/2010．
<gadget id="calculator">1 + 2_010</gadget>
<output>2_011</output>

<gadget id="calculator">2_010 / 2</gadget>
<output>1_005</output>

<gadget id="calculator">2_011 * 1_005</gadget>
<output>2_021_055</output>

<gadget id="calculator">2_009 + 1</gadget>
<output>2_010</output>

<gadget id="calculator">2_009 / 2</gadget>
<output>2_009/2 = around 1_004.5</output>

<gadget id="calculator">2_010 * (2_009/2)</gadget>
<output>2_019_045</output>

<gadget id="calculator">2_021_055 + 2_019_045</gadget>
<output>4_040_100</output>

<gadget id="calculator">4_040_100 / 2_010</gadget>
<output>2_010</output>

<result>2_010</result>