Wang Dan's mother bought a two-year bond with an annual interest rate of 3.8%, and the interest due after maturity was 342 yuan. How much did Wang Dan's mother buy this bond?
王丹妈妈购买了年利率为3.8%的二年期债劵，到期后应得利息342元，王丹妈妈购买了这种债劵多少元？
<gadget id="calculator">3.8 / 100</gadget>
<output>0.038</output>

<gadget id="calculator">342 / 2 / 0.038</gadget>
<output>4_500</output>

<result>4_500</result>