If ☆*□=25, then (5*☆)*(□*4)=how much.
如果☆*□=25，那么(5*☆)*(□*4)=多少．
<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<gadget id="calculator">25 * 20</gadget>
<output>500</output>

<result>500</result>