A piece of iron wire is 5 meters long, cut (4/5) first, and then cut (4/5) meters, how many meters are left at this time?
一根铁丝长5米，先剪(4/5)下，又剪下(4/5)米，这时还余下多少米．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

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

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

<result>1/5 = around 0.2</result>