Using 6, 7, 8, 9 to form a three-digit number and a one-digit number, what is the maximum product of them?
用6、7、8、9四个数字组成一个三位数和一个一位数，它们乘积最大是多少．
<gadget id="calculator">876 * 9</gadget>
<output>7_884</output>

<result>7_884</result>