There is a square flower bed, and one tree should be planted at each of the four corners. If 8 trees are planted on each side, how many trees should be planted in total?
有一个正方形的花坛，要在四个角上都栽1棵树，如果每边栽8棵，一共要栽多少棵？
<gadget id="calculator">8 * 4</gadget>
<output>32</output>

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

<result>28</result>