Wang Chang plans to finish a book in 15 days. I actually read 8 pages a day, but ended up delaying reading it by 3 days. How many pages does this book have?
王畅计划15天看完一本书．实际每天看8页，结果推迟3天才看完．这本书共有多少页？
<gadget id="calculator">15 + 3</gadget>
<output>18</output>

<gadget id="calculator">18 * 8</gadget>
<output>144</output>

<result>144</result>