For two numbers a and b, stipulate a⊙b=a*b-(a+b), try to calculate 6⊙2.
对于两个数a和b，规定a⊙b=a*b-(a+b)，试计算6⊙2．
<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<gadget id="calculator">6 + 2</gadget>
<output>8</output>

<gadget id="calculator">12 - 8</gadget>
<output>4</output>

<result>4</result>