Mom deposited 3,000 yuan in the bank on April 29, 2008, for three years, with an annual interest rate of 2.25%, and then paid 20% interest tax. How much is the principal and after-tax interest that the mother will get when it expires this year.
妈妈2008年4月29日存入银行3000元，定期三年，年利率2.25%，再交纳20%的利息税．今年到期妈妈可得本金和税后利息多少元．
<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">3_000 * 0.0225 * 3 * (4/5)</gadget>
<output>162</output>

<gadget id="calculator">162 + 3_000</gadget>
<output>3_162</output>

<result>3_162</result>