Xiaojun miscalculated 5*(□+3) as 5*□+3, how much difference between the result he got and the correct result
小军把5*(□+3)错算成了5*□+3，他得到的结果与正确的结果相差多少
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">15 - 3</gadget>
<output>12</output>

<result>12</result>