In a community, 38 trees are planted this year, and the number of trees planted this year is 7 times less than that of last year. How many trees did you plant last year?
一个小区，今年植树38棵，今年植树的棵数比去年的3倍还少7棵．去年植树多少棵？
<gadget id="calculator">38 + 7</gadget>
<output>45</output>

<gadget id="calculator">45 / 3</gadget>
<output>15</output>

<result>15</result>