(3/4) of an iron wire is used up, and there are 15 meters left. How long is the wire in meters.
一根铁丝用去它的(3/4)，还剩15米．铁丝全长多少米．
<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">15 / (1/4)</gadget>
<output>60</output>

<result>60</result>