In the school planting, 84 trees were planted in the fourth grade, which is twice the number of trees planted in the third grade. The number of trees planted in the fifth grade was 18 more than the total number of trees planted in the third and fourth grades. How many trees were planted in the fifth grade?
学校植树，四年级植树84棵，是三年级植树的2倍，五年级植树的棵数比三、四年级两个年级植树的总和还多18棵，五年级植树多少棵？
<gadget id="calculator">84 / 2</gadget>
<output>42</output>

<gadget id="calculator">84 + 42</gadget>
<output>126</output>

<gadget id="calculator">126 + 18</gadget>
<output>144</output>

<result>144</result>