Given that the three numbers are 2, 3, and 4, please write another number so that these four numbers can form a ratio. What can this number be (just write one number).
已知三个数为2，3，4，请你再写出一个数，使这四个数能组成一个比例，这个数可以是多少(只要写出一个数)．
<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<result>6</result>