Plant trees on one side of the path from one end. If one tree is planted every 4 meters, 37 trees need to be planted. If it is changed to one tree every 6 meters, how many trees can be left without moving.
小路的一边从一端种树．每隔4米种一棵，需种37棵树，如果改成每隔6米种一棵，可有多少棵树不动．
<gadget id="calculator">37 - 1</gadget>
<output>36</output>

<gadget id="calculator">36 * 4</gadget>
<output>144</output>

<gadget id="calculator">144 / 12</gadget>
<output>12</output>

<gadget id="calculator">12 + 1</gadget>
<output>13</output>

<result>13</result>