On Arbor Day, Guangming Primary School held a tree-planting competition. The third grade students planted 102 small saplings, twice as much as the second grade students; the fourth and fifth grade students planted 18 fewer than the second and third grade students. How many trees are planted in grade?
植树节，光明小学进行植树比赛，三年级同学植了102棵小树苗，是二年级同学植的2倍；四、五年级同学比二、三年级植的2倍少18棵，问四、五年级共植树多少棵？
<gadget id="calculator">102 / 2</gadget>
<output>51</output>

<gadget id="calculator">102 + 51</gadget>
<output>153</output>

<gadget id="calculator">153 * 2</gadget>
<output>306</output>

<gadget id="calculator">306 - 18</gadget>
<output>288</output>

<result>288</result>