Uncle Chen's monthly income was 2,400 yuan. According to regulations, the part exceeding 1,600 yuan should pay personal income tax at 5%. How much personal income tax should Uncle Chen pay last month?
陈叔叔上月收入2400元，按规定超过1600元的部分应按5%缴纳个人所得税．陈叔叔上个月应缴纳个人所得税多少元？
<gadget id="calculator">2_400 - 1_600</gadget>
<output>800</output>

<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">800 * (1/20)</gadget>
<output>40</output>

<result>40</result>