The fourth grade students of a school planted 45 trees, the fifth grade planted twice as many trees as the fourth grade, and the sixth grade planted 15 more trees than the fourth and fifth graders. How many trees will the sixth grade plant?
某校小学四年级同学植树45棵，五年级植的棵数是四年级的2倍，六年级植的比四、五年级植的总数还多15棵．六年级植树多少棵？
<gadget id="calculator">45 * 2</gadget>
<output>90</output>

<gadget id="calculator">45 + 90 + 15</gadget>
<output>150</output>

<result>150</result>