There are 12 bookshelves in the school library, with an average of 560 books on each shelf, and 1,870 books have been lent to students. How many books are there in the library?
学校图书馆共有12个书架，平均每个书架上放书560本，现已借给学生1870本，问图书馆里还有书多少本？
<gadget id="calculator">560 * 12</gadget>
<output>6_720</output>

<gadget id="calculator">6_720 - 1_870</gadget>
<output>4_850</output>

<result>4_850</result>