Uncle Liu deposits 50,000 yuan in the bank for two years, with an annual interest rate of 5% and an interest tax rate of 20%. How much will Uncle Liu get after tax when it matures?
刘叔叔把5万元存入银行，存期两年，年利率为5%，利息税率是20%，到期刘叔叔可得税后利息多少元．
<gadget id="calculator">5 * 10_000</gadget>
<output>50_000</output>

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

<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">50_000 * (1/20) * 2 * (4/5)</gadget>
<output>4_000</output>

<result>4_000</result>