The weight of 1 fox is equivalent to the weight of 2 chickens, the weight of 1 chicken is equivalent to the weight of 2 ducklings, and the weight of how many ducklings is equivalent to the weight of 1 fox.
1只狐狸的重量相当于2只鸡的重量，1只鸡的重量相当于2只小鸭的重量，多少只小鸭的重量相当于1只狐狸的重量．
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<result>4</result>