If 2x+3=15, then 3x+2=how much.
如果2x+3=15，那么3x+2=多少．
<gadget id="calculator">15 - 3</gadget>
<output>12</output>

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

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

<gadget id="calculator">18 + 2</gadget>
<output>20</output>

<result>20</result>