There are 18 poplar trees in the school, which are less than willow trees (1/10). How many willow trees are there? (solution by equation)
学校里有杨树18棵，比柳树少(1/10)，柳树有多少棵？(用方程解)
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">18 / (9/10)</gadget>
<output>20</output>

<result>20</result>