Xiao Ming has a story book. He read 16 pages on the first day and 20% on the second day, leaving 56 pages. How many pages are there in this book?
小明有一本故事书，第一天看了16页，第二天看了20%，还剩下56页，这本书共有多少页？
<gadget id="calculator">16 + 56</gadget>
<output>72</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">72 / (4/5)</gadget>
<output>90</output>

<result>90</result>