The sixth grade students planted trees. The first class planted 90 trees, 20% more than the second class, and the second class planted 25% less than the third class. How many trees did the third class plant?
六年级同学植树，一班植了90棵，比二班多植了20%，二班又比三班少植了25%，三班植了多少棵树？
<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">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">90 / (6/5) / (3/4)</gadget>
<output>100</output>

<result>100</result>