Spring is here, and the school divides the tree planting task between the sixth grade and the fifth grade according to the ratio of 10:7. The sixth grade actually planted 60 trees, 20% more than the original assignment. How many trees were originally planned to be planted by fifth graders?
春天到了，学校把植树任务按10：7分给六年级和五年级．六年级实际栽了60棵，超过原分配任务20%．原计划五年级同学栽多少棵树．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">60 / (6/5)</gadget>
<output>50</output>

<gadget id="calculator">7 / 10</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">50 * (7/10)</gadget>
<output>35</output>

<result>35</result>