Chickens and rabbits are in the same cage. There are 23 heads and 56 legs. How many chickens are there?
鸡兔同笼，有23个头，56条腿，鸡有多少只．
<gadget id="calculator">23 * 4</gadget>
<output>92</output>

<gadget id="calculator">92 - 56</gadget>
<output>36</output>

<gadget id="calculator">4 - 2</gadget>
<output>2</output>

<gadget id="calculator">36 / 2</gadget>
<output>18</output>

<result>18</result>