It is stipulated that a*b=4a-2b, then 9*6=how much.
规定a*b=4a-2b，则9*6=多少．
<gadget id="calculator">9 * 4</gadget>
<output>36</output>

<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<gadget id="calculator">36 - 12</gadget>
<output>24</output>

<result>24</result>