A steel pipe, use (1/5) of the total for the first time, use the rest (1/4) for the second time, use (1/2) the rest of the second time for the third time, and use up the rest 3 meters, how many meters is this steel pipe?
一根钢管，第一次用去总数的(1/5)，第二次用去剩下的(1/4)，第三次用去第二次剩下的(1/2)，还剩3米，这根钢管多少米？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

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

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

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(4/5) * (3/4) * (1/2)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 - (1/5) - (1/5) - (3/10)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">3 / (3/10)</gadget>
<output>10</output>

<result>10</result>