Mr. Zhang received a monthly salary of 1,200 yuan on June 10. According to the personal income tax law, the part of the monthly personal income exceeding 800 yuan should be levied a personal income tax at a rate of 5%. How much personal income tax should Mr. Zhang pay this month?
张老师6月10日领得当月工资1200元，按照个人所得税法规定，每月个人收入超过800元的部分，应按5%的税率征收个人所得税．张老师这个月应交纳个人所得税多少元？
<gadget id="calculator">1_200 - 800</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>