Aunt Zhang bought 20,000 yuan of five-year national construction bonds with an annual interest rate of 3.18%. How much can he get back the principal and interest at maturity?
张大妈买了20000元五年期的国家建设债券，年利率是3.18%．到期时他可以取回本金和利息一共多少元．
<gadget id="calculator">3.18 / 100</gadget>
<output>0.0318</output>

<gadget id="calculator">20_000 * 0.0318 * 5</gadget>
<output>3_180</output>

<gadget id="calculator">20_000 + 3_180</gadget>
<output>23_180</output>

<result>23_180</result>