A road is 1000 meters long, and (2/5) of it has been repaired. How many meters can be repaired to repair half of the road?
一条公路长1000米，已经修了它的(2/5)，再修多少米就能修好这条路的一半？
<gadget id="calculator">1_000 / 2</gadget>
<output>500</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1_000 * (2/5)</gadget>
<output>400</output>

<gadget id="calculator">500 - 400</gadget>
<output>100</output>

<result>100</result>