Zhang Hong has a deposit of 3,000 yuan, which was deposited in the bank on June 1 last year, for one year, with an annual interest rate of 2.25% and interest tax of 20%. On June 1 this year, she withdrew the interest on her savings (after paying taxes) and bought extracurricular books for the "hand in hand" children. How much did Zhang Hong pay for extracurricular books?
张红同学有3000元的存款，是去年6月1日存入银行的，定期一年，年利率为2.25%，利息税为20%．今年6月1日，她将自己存款的利息(缴税后)取出来，全都给"手拉手"的小朋友买了课外书．张红买课外书的钱是多少元？
<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 * 1 * (4/5)</gadget>
<output>54</output>

<result>54</result>