Xiaojun mistook (4+□)*15 as 4+□*15, how much is the difference between his calculated result and the correct result
小军把(4+□)*15错看成4+□*15，他算出的结果与正确的结果相差多少
<gadget id="calculator">60 - 4</gadget>
<output>56</output>

<result>56</result>