On February 13, 2006, Xiaodong deposited 1,000 yuan of New Year's money in the bank, and the lump sum deposit was withdrawn for one year, with an annual interest rate of 2.25%. When the plan expires, the after-tax interest will be donated to the "Hope Project" to support out-of-school children in poor areas. How much can Xiaodong donate to the "Hope Project" when it expires?
小东2006年2月13日把1000元压岁钱存入银行，整存整取一年，年利率是2.25%．准备到期后把税后利息捐赠给"希望工程"，支援贫困地区的失学儿童，到期时小东可以捐赠给"希望工程"多少元．
<gadget id="calculator">2.25 / 100</gadget>
<output>0.0225</output>

<gadget id="calculator">1_000 * 0.0225 * 1</gadget>
<output>22.5</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">22.5 * (4/5)</gadget>
<output>18</output>

<result>18</result>