Little Ding Ding wrote 5*(□+4) as 5*□+4 by mistake, how much is the difference between the number it calculates and the correct answer.
小丁丁把5*(□+4)错写成5*□+4，它算出的得数与正确答案相差多少．
<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<gadget id="calculator">20 - 4</gadget>
<output>16</output>

<result>16</result>