Mr. Wang deposited 20,000 yuan in the bank for a period of one year, and the pre-tax interest and principal after maturity totaled 20,700 yuan. What is the annual interest rate?
王老师把20000元存入银行，存期一年，到期后的税前利息和本金共20700元．年利率是多少？
<gadget id="calculator">20_700 - 20_000</gadget>
<output>700</output>

<gadget id="calculator">700 / 20_000 / 1</gadget>
<output>7/200 = around 0.035</output>

<result>7/200 = around 0.035</result>