There are 8 willow trees planted in the front, back, left and right of the flower bed. How many willow trees are planted in total?
花坛里前、后、左、右都种了8棵柳树，一共种了多少棵柳树？
<gadget id="calculator">8 * 4</gadget>
<output>32</output>

<gadget id="calculator">32 - 4</gadget>
<output>28</output>

<result>28</result>