Plant trees around a square playground. It is required to plant one tree in each of the four corners, and plant 12 trees on each side. How many trees should be planted in total?
在一个正方形的操场上四周植树，要求4个角各植1棵，每边都植12棵，一共要植树多少棵．
<gadget id="calculator">12 * 4</gadget>
<output>48</output>

<gadget id="calculator">48 - 4</gadget>
<output>44</output>

<result>44</result>