There are 1500 grams of water in the cup, and 1 kilogram is drunk, how many grams are left?
杯子里原有1500克水，喝了1千克，还剩多少克？
<gadget id="calculator">1 * 1_000</gadget>
<output>1_000</output>

<gadget id="calculator">1_500 - 1_000</gadget>
<output>500</output>

<result>500</result>