Xiao Ming reads a book, reads 60% of the whole book on the first day, and leaves 50 pages unread, how many pages does this book have?
小明读一本书，第一天看全书的60%，还剩50页没有看，这本书有多少页？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">50 / (2/5)</gadget>
<output>125</output>

<result>125</result>