In ☆/7=12...□, when □ is the largest, what is ☆?
在☆/7=12…□中，当□最大时，☆是多少．
<gadget id="calculator">7 * 12</gadget>
<output>84</output>

<gadget id="calculator">7 - 1</gadget>
<output>6</output>

<gadget id="calculator">84 + 6</gadget>
<output>90</output>

<result>90</result>