Xiao Wang deposits 4,000 yuan in the bank for 2 years, with an annual interest rate of 2.25%. How much after-tax interest can he get at maturity.
小王把4000元钱存入银行，定期2年，年利率是2.25%．到期时，他可得税后利息多少元．
<gadget id="calculator">2.25 / 100</gadget>
<output>0.0225</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">4_000 * 0.0225 * 2 * (4/5)</gadget>
<output>144</output>

<result>144</result>