A piece of iron wire is 1 km long, 50 meters have been used, how many meters are left?
一根铁丝长1千米，用了50米，还剩多少米．
<gadget id="calculator">1 * 1_000</gadget>
<output>1_000</output>

<gadget id="calculator">1_000 - 50</gadget>
<output>950</output>

<result>950</result>