□/9=57…□, when the remainder is the largest, what is the dividend.
□/9=57…□，当余数最大时，被除数是多少．
<gadget id="calculator">57 * 9</gadget>
<output>513</output>

<gadget id="calculator">9 - 1</gadget>
<output>8</output>

<gadget id="calculator">513 + 8</gadget>
<output>521</output>

<result>521</result>