■/▲=9...6, ■What is the minimum.
■/▲=9…6，■最小是多少．
<gadget id="calculator">6 + 1</gadget>
<output>7</output>

<gadget id="calculator">7 * 9</gadget>
<output>63</output>

<gadget id="calculator">63 + 6</gadget>
<output>69</output>

<result>69</result>