The school distributes homework books. There are 25 classes, and each class distributes 144, and 80 copies are kept as spares. How many homework books should the school buy?
学校发作业本，有25个班，每班发144，还要留80本作为备用品，学校应该买多少本作业本？
<gadget id="calculator">144 * 25</gadget>
<output>3_600</output>

<gadget id="calculator">3_600 + 80</gadget>
<output>3_680</output>

<result>3_680</result>