12 plus (1/3) of a number, the sum is 18, find this number.
12加上一个数的(1/3)，和是18，求这个数．
<gadget id="calculator">18 - 12</gadget>
<output>6</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">6 / (1/3)</gadget>
<output>18</output>

<result>18</result>