The careless naughty counted 6*(a+4) as 6a+4, how much more than the correct result.
粗心的淘气把6*(a+4)算成了6a+4，结果比正确得数多少．
<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<gadget id="calculator">24 - 4</gadget>
<output>20</output>

<result>20</result>