On January 1 this year, Xiaohua deposited 50 yuan of pocket money in the bank for a period of one year, and planned to donate the interest and principal together to the Hope Project to support children in impoverished mountainous areas. If the annual interest rate is calculated at 2.25%, and the interest tax is calculated at 20%, how much can Xiaohua donate to Hope Project by January 1 next year?
小华今年1月1日把积蓄下来的零用钱50元存入银行，定期一年，准备到期后把利息和本金一起捐给希望工程，支援贫困山区的儿童．如果年利率按2.25%计算，利息税按20%计算，到明年1月1日小华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">50 * 0.0225 * 1</gadget>
<output>1.125</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">1.125 * (4/5)</gadget>
<output>0.9</output>

<gadget id="calculator">50 + 0.9</gadget>
<output>50.9</output>

<result>50.9</result>