A highway is 320 kilometers long and has been repaired (4/5). How many kilometers are left?
一条公路长320千米，已经修了(4/5)，还剩多少千米．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">320 * (1/5)</gadget>
<output>64</output>

<result>64</result>