Xiao Ming reads a book (1/4) in 5 days. At this rate, how many days will it take him to finish reading this book?
小明5天看了一本书的(1/4)，照这样的速度，他看完这本书要多少天．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/4) / 5</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / (1/20)</gadget>
<output>20</output>

<result>20</result>