In November 2007, the annual interest rate of the two-year time deposit was 4.5%, and a 5% interest tax was required to be paid when it matured. Mom has 40,000 yuan for two years, how much is the taxable interest when it expires.
2007年11月，二年定期存款的年利率是4.5%，到期时需要缴纳5%的利息税．妈妈有40000元定期二年，到期时可得税利息是多少元．
<gadget id="calculator">4.5 / 100</gadget>
<output>0.045</output>

<gadget id="calculator">40_000 * 2 * 0.045</gadget>
<output>3_600</output>

<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 - (1/20)</gadget>
<output>19/20 = around 0.95</output>

<gadget id="calculator">3_600 * (19/20)</gadget>
<output>3_420</output>

<result>3_420</result>