Grandma raised 20 roosters, and the number of hens was half that of roosters. How many chickens did she raise in total?
奶奶养了20只公鸡，母鸡的只数是公鸡的一半，一共养了多少只鸡．
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">20 + 10</gadget>
<output>30</output>

<result>30</result>