Let a and b represent numbers, and it is stipulated that a★b represents 6a-2b, then 3★4=how much.
设a、b表示数，规定a★b表示6a-2b，那么3★4=多少．
<gadget id="calculator">6 * 3</gadget>
<output>18</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">18 - 8</gadget>
<output>10</output>

<result>10</result>