In a technical book, Xiao Ming has read 50 pages and left 31 pages unread. What percentage of the book does the number of unread pages account for?
一本科技书，小明看过50页，还剩下31页没有看，没看过的页数占这本书的几分之几？
<gadget id="calculator">50 + 31</gadget>
<output>81</output>

<gadget id="calculator">31 / 81</gadget>
<output>31/81 = around 0.382716</output>

<result>31/81 = around 0.382716</result>