To build a 500-meter road, (2/5) has been built, how many meters are left?
修一条500米的公路，已经修了(2/5)，还剩下多少米？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">500 * (3/5)</gadget>
<output>300</output>

<result>300</result>