There are 60 chickens and rabbits, and the chickens and rabbits have the same number of legs. How many chickens are there?
有鸡和兔共60只，鸡和兔的腿数相同，鸡有多少只．
<gadget id="calculator">4 + 2</gadget>
<output>6</output>

<gadget id="calculator">240 / 6</gadget>
<output>40</output>

<result>40</result>