Xiao Ming miscalculated 30*(□+3) as 30*□+3, how much difference is the result he got from the correct result?
小明把30*(□+3)错算成30*□+3，他得到的结果与正确的结果相差多少？
<gadget id="calculator">30 * 3</gadget>
<output>90</output>

<gadget id="calculator">90 - 3</gadget>
<output>87</output>

<result>87</result>