A road is 3 kilometers long, and a road repair team built 2500 meters, how many meters are left
一条路长3千米，一个修路队修了2500米，还剩下多少米
<gadget id="calculator">3 * 1_000</gadget>
<output>3_000</output>

<gadget id="calculator">3_000 - 2_500</gadget>
<output>500</output>

<result>500</result>