Xiaohong miscalculated 7*(□+5) as 7*□+5. How much is the difference between the number she calculated and the correct answer?
小红把7*(□+5)错算成了7*□+5，她算出的得数与正确答案相差多少．
<gadget id="calculator">7 * 5</gadget>
<output>35</output>

<gadget id="calculator">35 - 5</gadget>
<output>30</output>

<result>30</result>