The farm raised 2,000 chickens last year, which is 500 more than the previous year. The number of chickens raised last year (1/5) is equal to the number of chickens raised this year (2/9), and the number of chickens raised this year is a percentage increase compared to the previous year. How much?
养殖场去年养鸡2000只，比前年多养500只，去年养鸡只数的(1/5)等于今年养鸡只数的(2/9)，今年养鸡的只数比前年增加百分之几？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">(1/5) / (2/9)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">2_000 * (9/10)</gadget>
<output>1_800</output>

<gadget id="calculator">2_000 - 500</gadget>
<output>1_500</output>

<gadget id="calculator">1_800 - 1_500</gadget>
<output>300</output>

<gadget id="calculator">300 / 1_500</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>