(4/5)km is 200m.
(4/5)km的多少是200m．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(4/5) * 1_000</gadget>
<output>800</output>

<gadget id="calculator">200 / 800</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>