Xiaoying reads an extra-curricular book during the summer vacation. She started reading it on July 2 and finished it on August 15. She reads 15 pages every day. How many pages are there in this extra-curricular book?
小英在暑假看一本课外书，她从7月2日开始看，8月15日正好看完，每天看15页，这本课外书有多少页．
<gadget id="calculator">31 - 2</gadget>
<output>29</output>

<gadget id="calculator">29 + 1 + 15</gadget>
<output>45</output>

<gadget id="calculator">15 * 45</gadget>
<output>675</output>

<result>675</result>