One of Uncle Wang's inventions won a scientific and technological achievement award of 4,000 yuan. According to regulations should pay 20% personal income tax. How much bonus did Uncle Wang actually get?
王叔叔的一项创造发明，得到了4000元的科技成果奖．按规定应缴纳20%的个人所得税．王叔叔实际得到奖金多少元．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">4_000 * (4/5)</gadget>
<output>3_200</output>

<result>3_200</result>