1+2+3+...+99+...+1000+1002+1004+...2004+2006=how much.
1+2+3+…+99+…+1000+1002+1004+…2004+2006=多少．
<gadget id="calculator">1 + 1_000</gadget>
<output>1_001</output>

<gadget id="calculator">1_000 / 2</gadget>
<output>500</output>

<gadget id="calculator">1_001 * 500</gadget>
<output>500_500</output>

<gadget id="calculator">1_002 + 2_006</gadget>
<output>3_008</output>

<gadget id="calculator">2_006 / 2</gadget>
<output>1_003</output>

<gadget id="calculator">1_003 / 2</gadget>
<output>1_003/2 = around 501.5</output>

<gadget id="calculator">3_008 * (1_003/2)</gadget>
<output>1_508_512</output>

<gadget id="calculator">500_500 + 1_508_512</gadget>
<output>2_009_012</output>

<result>2_009_012</result>