Mr. Zhang deposits 20,000 yuan in the bank for 5 years, with an annual interest rate of 3.2%. How much is the after-tax interest Mr. Zhang can get upon maturity. (Note: Interest tax is 20%)
张老师存银行20000元，定期5年，年利率3.2%，到期张老师可得税后利息多少元．(注：利息税按20%)
<gadget id="calculator">3.2 / 100</gadget>
<output>0.032</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">20_000 * 0.032 * 5 * (4/5)</gadget>
<output>2_560</output>

<result>2_560</result>