piece of steel is 8 meters long, and it takes (3/8) meters to make a part. 20 such parts have been made, how many meters are left?
一段钢材长8米，做一个零件用(3/8)米．已经做了20个这样的零件，还剩多少米？
<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">20 * (3/8)</gadget>
<output>15/2 = around 7.5</output>

<gadget id="calculator">8 - (15/2)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>