There is a small road from Xiaoxiong's house to Xiaozhu's house, a tree is planted every 45 meters, and a total of 53 trees are planted at both ends; now it is changed to plant a tree every 60 meters. Find out how many trees are left.
从小熊家到小猪家有一条小路，每隔45米种一棵树，加上两端共种53棵；现在改成每隔60米种一棵树．求可余下多少棵树．
<gadget id="calculator">53 - 1</gadget>
<output>52</output>

<gadget id="calculator">45 * 52</gadget>
<output>2_340</output>

<gadget id="calculator">2_340 / 180</gadget>
<output>13</output>

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

<result>12</result>