Xiao Ming reads a book. He reads half of the book on the first day, the remaining half on the second day, and reads the entire book after reading 18 pages on the third day. How many pages does the book have?
小明看一本书，第一天看了这本书的一半，第二天看了剩下的一半，第三天看了18页将书全看完，这本书一共有多少页？
<gadget id="calculator">18 * 2 * 2</gadget>
<output>72</output>

<result>72</result>