Mingming especially likes to read "Children's Encyclopedia". He read 100 pages in 5 days, and it took him another 25 days to finish this book. How many pages does this book have?
明明特别喜欢看《少儿百科全书》，他5天看了100页，像这样又看了25天才把这本书看完，这本书一共有多少页？
<gadget id="calculator">40 * 20</gadget>
<output>800</output>

<result>800</result>