Last month, Xiaoming’s father paid 1,600 yuan in salary. According to regulations, the part of the monthly personal income exceeding 800 yuan should pay 20% personal income tax. How much was Xiaoming’s father’s after-tax income last month?
上个月小明爸爸发工资1600元，按规定每月个人收入超过800元的部分，应缴纳20%的个人所得税，小明爸爸上个月税后收入是多少元？
<gadget id="calculator">1_600 - 800</gadget>
<output>800</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">800 * (1/5)</gadget>
<output>160</output>

<gadget id="calculator">1_600 - 160</gadget>
<output>1_440</output>

<result>1_440</result>