A wire is 300 meters long, and after 40% of it is used up, how many meters are left?
一根电线长300米，用了40%后，还剩下多少米．
<gadget id="calculator">40 / 100</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">300 * (3/5)</gadget>
<output>180</output>

<result>180</result>