When 3x+6=15, then 6x+6=how much.
当3x+6=15时，则6x+6=多少．
<gadget id="calculator">15 - 6</gadget>
<output>9</output>

<gadget id="calculator">9 / 3</gadget>
<output>3</output>

<gadget id="calculator">6 * 3</gadget>
<output>18</output>

<gadget id="calculator">18 + 6</gadget>
<output>24</output>

<result>24</result>