Xiao Ming's mother deposited Xiao Ming's New Year's money in the bank two years ago. At that time, the bank interest rate was 3.5%. After deducting the 20% interest tax this year, she got 280 yuan in interest. Ask: How much was Xiao Ming's New Year's money two years ago?
小明的妈妈两年前将小明的压岁钱存入银行，当时银行利率是3.5%，今年去除20%的利息税后，拿到了280元的利息，问：两年前小明的压岁钱是多少元？
<gadget id="calculator">3.5 / 100</gadget>
<output>0.035</output>

<gadget id="calculator">0.035 * 2</gadget>
<output>0.07</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">0.035 * 2 * (1/5)</gadget>
<output>0.014</output>

<gadget id="calculator">0.07 - 0.014</gadget>
<output>0.056</output>

<gadget id="calculator">280 / 0.056</gadget>
<output>5_000</output>

<result>5_000</result>