☆/8=39...□, to make the number in □ the largest, how much should ☆ be.
☆/8=39…□，要使□里的数最大，☆应是多少．
<gadget id="calculator">8 * 39</gadget>
<output>312</output>

<gadget id="calculator">8 - 1</gadget>
<output>7</output>

<gadget id="calculator">312 + 7</gadget>
<output>319</output>

<result>319</result>