Xiao Ming reads a 400-page book, and he reads 64 pages in 8 days. Based on this calculation, how many days does it take Xiao Ming to finish the book?
小明看一本400页的书，他8天看了64页，照这计算，小明看完这本书共需多少天？
<gadget id="calculator">64 / 8</gadget>
<output>8</output>

<gadget id="calculator">400 / 8</gadget>
<output>50</output>

<result>50</result>