If A※B=20/A-2*B, then (4※2)※3=how much.
如果A※B=20/A-2*B，那么(4※2)※3=多少．
<gadget id="calculator">5 - 4</gadget>
<output>1</output>

<gadget id="calculator">20 / 1</gadget>
<output>20</output>

<gadget id="calculator">2 * 3</gadget>
<output>6</output>

<gadget id="calculator">20 - 6</gadget>
<output>14</output>

<result>14</result>