Uncle Zhang's monthly salary is 2,400 yuan. According to the regulations of personal income tax, the balance after deducting 2,000 yuan from the monthly salary shall be paid personal income tax at a rate of 5%. How much personal income tax should Uncle Zhang pay every month?
张叔叔月工资是2400元．按个人所得税的规定，每月工资扣除2000元后的余额部分，按5%的比例缴纳个人所得税．张叔叔每月应缴纳个人所得税多少元？
<gadget id="calculator">2_400 - 2_000</gadget>
<output>400</output>

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

<gadget id="calculator">400 * (1/20)</gadget>
<output>20</output>

<result>20</result>