The school bought 800 books and distributed them to 12 classes in the fourth grade. Each class distributed 45 books. How many books are left?
学校买来800本图书，发给四年级12个班的同学，每个班发了45本，还剩多少本图书？
<gadget id="calculator">45 * 12</gadget>
<output>540</output>

<gadget id="calculator">800 - 540</gadget>
<output>260</output>

<result>260</result>