Xiaohong reads a book. In the first week, she reads 20% of the whole book and there are 10 pages more. At this time, there are still 70 pages that she has not read. How many pages does this book have?
小红看一本书，第一周看了全书的20%还多10页，这时还有70页没有看．这本书共有多少页？
<gadget id="calculator">70 + 10</gadget>
<output>80</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">80 / (4/5)</gadget>
<output>100</output>

<result>100</result>