On Arbor Day last year, the number of trees planted by the fifth grade students in our school belonged to the sixth grade students (5/21), and the number of trees planted by the fourth grade students was that of the fifth grade students (4/5). 310 trees, how many trees will the sixth grade students plant?
在去年植树节那天，我校五年级同学植树的棵树是六年级同学的(5/21)，四年级同学植树的棵数是五年级同学的(4/5)，如果三个年级共植树310棵，那么六年级同学植树多少棵？
<gadget id="calculator">5 / 21</gadget>
<output>5/21 = around 0.238095</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(5/21) * (4/5)</gadget>
<output>4/21 = around 0.190476</output>

<gadget id="calculator">1 + (5/21) + (4/21)</gadget>
<output>10/7 = around 1.428571</output>

<gadget id="calculator">310 / (10/7)</gadget>
<output>217</output>

<result>217</result>