A and B represent two numbers, define A*B to represent ((A+B)/2), then what is the value of ((1*9)*9)*6.
A、B表示两个数，定义A*B表示((A+B)/2)，则((1*9)*9)*6的值是多少．
<gadget id="calculator">7 + 6</gadget>
<output>13</output>

<gadget id="calculator">13 / 2</gadget>
<output>13/2 = around 6.5</output>

<result>13/2 = around 6.5</result>