The school bought a batch of books and distributed them to 23 classes on average. Each class got 105 books, and there were 78 books left. How many books did the school buy in total?
学校买来一批图书，平均分给23个班，每个班分得105本，还剩78本．学校一共买来多少本图书？
<gadget id="calculator">105 * 23</gadget>
<output>2_415</output>

<gadget id="calculator">2_415 + 78</gadget>
<output>2_493</output>

<result>2_493</result>