There are 280 children's books in the library, and they are lent to 8 classes. Each class has 25 books. How many books are left?
图书室有少儿读物280本，借给8个班，每班25本，还剩多少本？
<gadget id="calculator">25 * 8</gadget>
<output>200</output>

<gadget id="calculator">280 - 200</gadget>
<output>80</output>

<result>80</result>