Xiao Ming reads a story book. He reads 25% of the whole book on the first day, and (2/5) of the whole book on the second day. There are still 70 pages left. How many pages are there in this book?
小明看一本故事书，第一天看了全书的25%，第二天看了全书的(2/5)，还剩下70页没看，这本书一共有多少页？
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">1 - (1/4) - (2/5)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">70 / (7/20)</gadget>
<output>200</output>

<result>200</result>