Xiao Ming deposits 500 yuan of New Year's money in the bank with a deposit period of 1 year and an annual interest rate of 2.25%. How much is the total amount of principal and after-tax interest after maturity?
小明把500元压岁钱存入银行，存期1年，年利率2.25%，到期后可得本金和税后利息一共多少元？
<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">500 * 0.0225 * 1 * (4/5)</gadget>
<output>9</output>

<gadget id="calculator">500 + 9</gadget>
<output>509</output>

<result>509</result>