Define a new operation: Given an operation P△Q=((P+Q)/3), what is the result of 3△(6△9)
定义新运算：已知一种运算P△Q=((P+Q)/3)，求3△(6△9)的得数是多少
<gadget id="calculator">6 + 9</gadget>
<output>15</output>

<gadget id="calculator">15 / 3</gadget>
<output>5</output>

<gadget id="calculator">3 + 5</gadget>
<output>8</output>

<gadget id="calculator">8 / 3</gadget>
<output>8/3 = around 2.666667</output>

<result>8/3 = around 2.666667</result>