Plant trees on the four sides of a square pond, and plant 10 trees on each side (one tree is planted on each of the four corners), how many trees are planted on the four sides?
在一个正方形的池塘四边上种树，每边种10棵(四个角上都种一棵)，四边一共种了多少棵？
<gadget id="calculator">10 * 4</gadget>
<output>40</output>

<gadget id="calculator">40 - 4</gadget>
<output>36</output>

<result>36</result>