There are 42 poplar trees, 3 times as many fir trees as poplar trees, and 28 fewer willow trees than their total number. How many willow trees are there?
有42棵杨树，杉树是杨树的3倍，柳树比它们的总数少28棵，柳树有多少棵？
<gadget id="calculator">42 * 3</gadget>
<output>126</output>

<gadget id="calculator">42 - 28</gadget>
<output>14</output>

<gadget id="calculator">126 + 14</gadget>
<output>140</output>

<result>140</result>