A steel pipe, after using up (3/4) of it, there are still 6 meters left, how many meters are used up?
一根钢管，用去它的(3/4)后，还剩下6米，用去了多少米．
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">6 / (1/4)</gadget>
<output>24</output>

<gadget id="calculator">24 - 6</gadget>
<output>18</output>

<result>18</result>