2+4+6+8+...+998+1000=how much.
2+4+6+8+…+998+1000=多少．
<gadget id="calculator">2 + 1_000</gadget>
<output>1_002</output>

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

<gadget id="calculator">500 / 2</gadget>
<output>250</output>

<gadget id="calculator">1_002 * 250</gadget>
<output>250_500</output>

<result>250_500</result>