A piece of steel is 4 meters long. It takes (3/20) meters to make one part, and 15 such parts have been made, how many meters are left?
一段钢材长4米．做一个零件用了(3/20)米，已经做了15个这样的零件，还剩多少米？
<gadget id="calculator">3 / 20</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">(3/20) * 15</gadget>
<output>9/4 = around 2.25</output>

<gadget id="calculator">4 - (9/4)</gadget>
<output>7/4 = around 1.75</output>

<result>7/4 = around 1.75</result>