After depositing 10,000 yuan in the bank for two years, Aunt Zhang obtained a total of 10,880 yuan in principal and interest from the bank. What is the annual interest rate?
张阿姨将1万元存入银行两年后，在银行取得本金和利息共10880元，年利率是多少？
<gadget id="calculator">10_880 - 10_000</gadget>
<output>880</output>

<gadget id="calculator">880 / 10_000 / 2 / 0.8</gadget>
<output>0.055</output>

<result>0.055</result>