Subtract half of a rope, then cut off the remaining half, leaving 3 meters, how many meters is the rope?
一根绳子减去一半，再剪去余下的一半，剩3米，绳子原来多少米？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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

<gadget id="calculator">(1/2) * (1/2)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/2) - (1/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">3 / (1/4)</gadget>
<output>12</output>

<result>12</result>