Xiaoli has been reading a book for 4 days, and now she reads 12 pages a day, which is exactly half of it in 5 days. How many pages does this book have?
一本书，小丽已看了4天，现在每天看12页，看了五天正好看了一半，这本书一共多少页？
<gadget id="calculator">12 * 5 * 2</gadget>
<output>120</output>

<result>120</result>