There are 10 tigers and chickens, and 26 legs. How many chickens?
老虎和鸡共10只，脚共26只．鸡多少只．
<gadget id="calculator">4 * 10</gadget>
<output>40</output>

<gadget id="calculator">40 - 26</gadget>
<output>14</output>

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

<gadget id="calculator">14 / 2</gadget>
<output>7</output>

<result>7</result>