It is known that 1 pig = 2 sheep; 1 sheep = 7 rabbits. Then 2 pigs = how many rabbits.
已知1头猪=2只羊；1只羊=7只兔子．那么2头猪=多少只兔子．
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">4 * 7</gadget>
<output>28</output>

<result>28</result>