The number of ducks is (3/7) the number of chickens, then the number of chickens is the number of ducks.
鸭的只数是鸡的只数的(3/7)，那么鸡的只数是鸭的只数的多少．
<gadget id="calculator">7 / 3</gadget>
<output>7/3 = around 2.333333</output>

<result>7/3 = around 2.333333</result>