There are two classes of students participating in labor, and they are divided into a batch of saplings. The number of saplings allocated to the first class is 100 more than 30% of the total, and the number of saplings allocated to the second class is 50 less than 60% of the total. How many trees.
有两班同学参加劳动，共分一批树苗，一班分得的棵数比总数的30%多100棵，二班分得的棵数比总数的60%少50棵，则这批树苗有多少棵．
<gadget id="calculator">100 - 50</gadget>
<output>50</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/10) - (3/5)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">50 / (1/10)</gadget>
<output>500</output>

<result>500</result>