The mode of the data 5, 6, x, 4 is equal to its mean, then x = how many.
数据5、6、x、4的众数等于它的平均数，则x=多少．
<gadget id="calculator">5 + 6 + 5 + 4</gadget>
<output>20</output>

<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<result>5</result>