Xiaohong reads a book. On the first day, she reads 10 more pages (1/7) of the whole book. On the second day, she reads 10 more pages than on the first day. At this time, there are still 30 pages that she has not read. How many pages does this book have?
小红看一本书，第一天看了全书的(1/7)多10页，第二天比第一天多看10页，这时还有30页没有看．这本书共有多少页？
<gadget id="calculator">10 + 10 + 10 + 30</gadget>
<output>60</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">(1/7) + (1/7)</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">1 - (2/7)</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">60 / (5/7)</gadget>
<output>84</output>

<result>84</result>