There are 120 books on the bookshelf, among which reference books account for 10%, technical books account for 45%, and the rest are literary books. How many literary books are there?
书架上有120本书，其中工具书占10%，科技书占45%，其余都是文艺书．文艺书有多少本？
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">45 / 100</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">1 - (1/10) - (9/20)</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">120 * (9/20)</gadget>
<output>54</output>

<result>54</result>