Xiaohong reads a story book. She reads (2/5) of this book on the first day, reads 45 pages on the second day, and leaves 15 pages unread. How many pages are there in this book?
小红读一本故事书，第一天读了这本书的(2/5)，第二天读了45页，还剩下15页没有读．这本书一共多少页？
<gadget id="calculator">45 + 15</gadget>
<output>60</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">60 / (3/5)</gadget>
<output>100</output>

<result>100</result>