A professor has a monthly salary of 3,500 yuan, and he also serves as a consultant for a middle school with a monthly salary of 2,500 yuan. According to the regulations, personal income tax is paid at 3% for the part exceeding 3,500 yuan and less than 5,000 yuan, and 10% for the portion between 5,000 yuan and 8,000 yuan. How much is the professor's monthly tax liability?
一位教授每月工资收入3500元，他还兼任一所中学的顾问，每月薪金2500元．按规定超出3500元不足5000元部分按3%缴纳个人所得税，5000元到8000元部分按10%缴纳个人所得税．这位教授每月应纳税多少元？
<gadget id="calculator">5_000 - 3_500</gadget>
<output>1_500</output>

<gadget id="calculator">3 / 100</gadget>
<output>3/100 = around 0.03</output>

<gadget id="calculator">1_500 * (3/100)</gadget>
<output>45</output>

<gadget id="calculator">2_500 - 3_500 - 1_500</gadget>
<output>-2_500</output>

<gadget id="calculator">3_500 + (-2_500)</gadget>
<output>1_000</output>

<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1_000 * (1/10)</gadget>
<output>100</output>

<gadget id="calculator">45 + 100</gadget>
<output>145</output>

<result>145</result>