I hope primary schools will plant trees. The third grade planted 150 trees, the fourth grade planted twice as many trees as the third grade, and the fifth grade planted 50 more trees than the total number of the third and fourth grades. How many trees were planted in the fifth grade?
希望小学去植树，三年级植了150棵，四年级植的是三年级的2倍，五年级植的比三四年级的总数还多50棵，五年级植树多少棵？
<gadget id="calculator">150 * 2</gadget>
<output>300</output>

<gadget id="calculator">150 + 300 + 50</gadget>
<output>500</output>

<result>500</result>