The original batch of books on the bookshelf totaled 120 books. After some of them were lent out, there were still 84 books left. How many books were loaned out?
书架上原有一批书共计120本，借出一些后还剩84本，借出多少本？
<gadget id="calculator">120 - 84</gadget>
<output>36</output>

<result>36</result>