The four-digit number 6AA2 is divisible by 9, A=how much.
四位数6AA2能被9整除，A=多少．
<gadget id="calculator">18 - 6 - 2</gadget>
<output>10</output>

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

<result>5</result>