The sixth grade students of Lixin Primary School planted 120 trees in spring, the fifth grade students planted 1/6 fewer trees than the sixth grade students, and 25% more trees than the fourth grade students. How many trees did the fourth grade students plant?
立新小学六年级学生春季共植树120棵，五年级学生比六年级学生少植树(1/6)，比四年级学生多植树25%，四年级学生植树多少棵？
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 - (1/6)</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">120 * (5/6)</gadget>
<output>100</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 + (1/4)</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">100 / (5/4)</gadget>
<output>80</output>

<result>80</result>