Calculation: (-1)+(+2)+(-3)+(+4)+...+(-99)+(+100)+...+(-2009)+(+2010).
计算：(-1)+(+2)+(-3)+(+4)+…+(-99)+(+100)+…+(-2009)+(+2010)．
<gadget id="calculator">2_010 - 2_009</gadget>
<output>1</output>

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

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

<result>1_005</result>