Xiaohong reads a book. On the first day, she reads 1/4 of the total number of pages in the book. On the second day, she reads 12 pages, leaving 27 pages unread. How many pages are there in this book?
小红看一本书，第一天看了全书总页数的(1/4)，第二天看了12页，还剩27页没看．这本书一共多少页？
<gadget id="calculator">12 + 27</gadget>
<output>39</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">39 / (3/4)</gadget>
<output>52</output>

<result>52</result>