There are 168 poplar trees in the botanical garden, which is 4 times that of pine trees. How many pine trees are there? What is the column
植物园有杨树168棵，是松树的4倍，有多少棵松树？列式是多少
<gadget id="calculator">168 / 4</gadget>
<output>42</output>

<result>42</result>