Subtract 2 from a number, multiply by 9, add 3, and finally divide by 4, the result is 12. Find this number.
某数减去2，乘以9，再加上3，最后除以4，结果等于12．求这个数．
<gadget id="calculator">12 * 4</gadget>
<output>48</output>

<gadget id="calculator">48 - 3</gadget>
<output>45</output>

<gadget id="calculator">45 / 9</gadget>
<output>5</output>

<gadget id="calculator">5 + 2</gadget>
<output>7</output>

<result>7</result>