There is a five-digit number, 3A0A1, which is a multiple of 9, A=how much.
有一个五位数，3A0A1，它是9的倍数，A=多少．
<gadget id="calculator">18 - 4</gadget>
<output>14</output>

<gadget id="calculator">14 / 2</gadget>
<output>7</output>

<result>7</result>