Xiao Ming reads a 420-page fairy tale book, and reads 120 pages in 8 days. According to this calculation, how many days will it take to finish reading this book?
小明读一本420页的童话书，8天读了120页，照这样计算，读完这本书要用多少天？
<gadget id="calculator">120 / 8</gadget>
<output>15</output>

<gadget id="calculator">420 / 15</gadget>
<output>28</output>

<result>28</result>