There are 270 more litchi trees in the orchard than longan trees, and the number of longan trees is 10% of that of litchi trees. Question: How many longan trees are there?
果园里的荔枝树比龙眼树多270棵，龙眼树的棵数是荔枝树的10%，问：龙眼树有多少棵？
<gadget id="calculator">10 / 100</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">270 / (9/10)</gadget>
<output>300</output>

<gadget id="calculator">300 * (1/10)</gadget>
<output>30</output>

<result>30</result>