A piece of cloth is used first (1/2) and then (1/4), and a total of 9 meters is used. How many meters is this piece of cloth?
一块布先用去(1/2)，又用去(1/4)，一共用去9米，这块布有多少米．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

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

<gadget id="calculator">(1/2) + (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">9 / (3/4)</gadget>
<output>12</output>

<result>12</result>