There are 80 poplar trees in the park, which are less than the number of pine trees (1/5), and the number of willow trees is more than that of pine trees (1/20). How many willow trees are there?
公园有杨树80棵，比松树棵数少(1/5)，柳树的棵数比松树多(1/20)，柳树有多少棵？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

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

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 + (1/20)</gadget>
<output>21/20 = around 1.05</output>

<gadget id="calculator">100 * (21/20)</gadget>
<output>105</output>

<result>105</result>