Subtract three times a number from 48 to get 12. Find this number.
从48里面减去一个数的3倍，得12，求这个数．
<gadget id="calculator">48 - 12</gadget>
<output>36</output>

<gadget id="calculator">36 / 3</gadget>
<output>12</output>

<result>12</result>