There are 100 chickens and rabbits, and the total number of legs is 344. How many rabbits are there?
有鸡和兔共100只，总脚数为344只．兔有多少只．
<gadget id="calculator">4 * 100</gadget>
<output>400</output>

<gadget id="calculator">400 - 344</gadget>
<output>56</output>

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

<gadget id="calculator">56 / 2</gadget>
<output>28</output>

<gadget id="calculator">100 - 28</gadget>
<output>72</output>

<result>72</result>