There is a square pond with one tree planted at each corner, if 6 trees are planted on each side, how many trees are planted along the pond?
有一个正方形池塘，4个角都栽一棵树，如果每边栽6棵，池塘边一共栽多少棵？
<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<gadget id="calculator">24 - 4</gadget>
<output>20</output>

<result>20</result>