The school bought some exercise books and distributed them to 5 classes, each class had 64 books, and there were 240 books left. How many exercise books did the school buy?
学校买来一些练习本，分给5个班，每班64本，还剩240本．学校买来多少本练习本？
<gadget id="calculator">64 * 5</gadget>
<output>320</output>

<gadget id="calculator">320 + 240</gadget>
<output>560</output>

<result>560</result>