Xiaoxiao deposited RMB 20,000 in the bank for three years, with an annual interest rate of 2.70%. After paying 20% interest income tax when due, how much is the principal and interest payable by the bank to Xiaoxiao?
笑笑在银行存了20000元人民币，定期三年，年利率是2.70%．到期时交纳利息所得税20%后，银行应付给笑笑本金和利息一共多少元？
<gadget id="calculator">2.7 / 100</gadget>
<output>0.027</output>

<gadget id="calculator">20_000 * 3 * 0.027</gadget>
<output>1_620</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">1_620 * (4/5)</gadget>
<output>1_296</output>

<gadget id="calculator">20_000 + 1_296</gadget>
<output>21_296</output>

<result>21_296</result>