In a certain farm, there are 500 chickens, which are 150 more than the number of ducks. What percentage is the number of ducks in this farm compared to chickens?
某饲养场，养鸡500只，比鸭的只数多150只，这个饲养场中鸭的只数是鸡的百分之几？
<gadget id="calculator">500 - 150</gadget>
<output>350</output>

<gadget id="calculator">350 / 500</gadget>
<output>7/10 = around 0.7</output>

<result>7/10 = around 0.7</result>