Xiao Zhang has deposited 1,200 yuan in the bank, with a deposit period of 3 years, an annual interest rate of 2.8%, and an interest tax of 20%. How much after-tax interest can he withdraw at maturity?
小张在银行存了1200元，存期3年，年利率是2.8%，利息税是20%，到期时，他可以取出税后利息多少元？
<gadget id="calculator">2.8 / 100</gadget>
<output>0.028</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_200 * 0.028 * 3 * (4/5)</gadget>
<output>80.64</output>

<result>80.64</result>