Chen Sicheng deposits 40,000 yuan in the bank for 10 years, with an annual interest rate of 3.25%. How much can he withdraw the principal and after-tax interest at maturity?
陈思诚把40000元存入银行，定期10年，年利率是3.25%，到期可以取出本金和税后利息共多少元．
<gadget id="calculator">3.25 / 100</gadget>
<output>0.0325</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">40_000 * 0.0325 * 10 * (4/5)</gadget>
<output>10_400</output>

<gadget id="calculator">40_000 + 10_400</gadget>
<output>50_400</output>

<result>50_400</result>