A 200-meter-long iron wire, the full length (1/5) is used on the first day, and the remaining (1/4) is used on the second day. How many meters is used on the second day?
一根200米长的铁丝，第一天用去全长的(1/5)，第二天用去余下的(1/4)，第二天用去多少米？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

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

<gadget id="calculator">200 * (4/5) * (1/4)</gadget>
<output>40</output>

<result>40</result>