Xiao Ming reads a book. He reads 20% of the whole book on the first day and 25% of the whole book on the second day. There are still 33 pages left to be read. How many pages are there in this book?
小明读一本书，第一天读了全书的20%，第二天读了全书的25%，还剩33页没有读完，这本书一共多少页？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/5) - (1/4)</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">33 / (11/20)</gadget>
<output>60</output>

<result>60</result>