A number multiplied by 3, subtracted by 8, divided by 2, and finally added to 4, the result is equal to 9. What is this number?
一个数乘3，减8，除以2，最后加上4，结果等于9．这个数是多少．
<gadget id="calculator">9 - 4</gadget>
<output>5</output>

<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<gadget id="calculator">10 + 8</gadget>
<output>18</output>

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

<result>6</result>