Ten years ago, Mr. Lin spent an average of 500 yuan per month in the first 5 months, and ended up in debt; in the last 7 months, he spent an average of 440 yuan a month, and finally paid off the debt owed, and the remaining 120 yuan. What is the average monthly salary of Mr. Zelin this year?
10年前，林老师前5个月中，平均每月支出500元，结果欠了债；在后7个月中，他平均每月支出440元，结果还清了所欠的债，且剩余120元．则林老师这一年平均每月的工资是多少元．
<gadget id="calculator">5 * 500</gadget>
<output>2_500</output>

<gadget id="calculator">7 * 440</gadget>
<output>3_080</output>

<gadget id="calculator">2_500 + 3_080 + 120</gadget>
<output>5_700</output>

<gadget id="calculator">5 + 7</gadget>
<output>12</output>

<gadget id="calculator">5_700 / 12</gadget>
<output>475</output>

<result>475</result>