There is a triangular land, the length of the three sides is 120 meters, if a tree is planted every 20 meters on the three sides, how many trees can be planted in total.
有一块三角形地，三条边的长度都是120米，如果在这三条边每隔20米种一棵树，那么一共可以种多少树．
<gadget id="calculator">3 / 20</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">120 * (3/20)</gadget>
<output>18</output>

<result>18</result>