The fourth grade students of Hongxing Primary School planted 45 trees, the number of trees planted by the fifth grade students was 18 times less than that of the fourth grade students, how many trees were planted by the fifth grade students?
红星小学四年级同学植树45棵，五年级同学植树的棵树比四年级的2倍少18棵，五年级同学植树多少棵？
<gadget id="calculator">45 * 2</gadget>
<output>90</output>

<gadget id="calculator">90 - 18</gadget>
<output>72</output>

<result>72</result>