On Arbor Day, the school organized students to plant trees, and the fifth-grade students planted 260 trees, 10 fewer than twice as many as the fourth-grade students. How many trees will the fourth graders plant?
植树节学校组织学生植树，五年级学生植树260棵，比四年级学生植树的2倍少10棵．四年级学生植树多少棵？
<gadget id="calculator">260 + 10</gadget>
<output>270</output>

<gadget id="calculator">270 / 2</gadget>
<output>135</output>

<result>135</result>