There are two bookshelves, A bookshelf has 110 books, and B bookshelf has 80 books. Each time, take 3 books from A bookshelf to B bookshelf.
有两个书架，甲书架有书110本，乙书架有书80本，每次从甲书架拿出3本到乙书架，拿多少次后两个书架的书相等．
<gadget id="calculator">110 - 80</gadget>
<output>30</output>

<gadget id="calculator">30 / 2 / 3</gadget>
<output>5</output>

<result>5</result>