A book has 84 pages in total, and Lili read 28 pages in the first 4 days. How many days will it take to finish this book? (Solve with ratio)
一本书共84页，丽丽前4天看了28页，照这样计算看完这本书一共需要多少天？(用比例解)
<gadget id="calculator">84 - 28</gadget>
<output>56</output>

<gadget id="calculator">4 / 28</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">56 * (1/7)</gadget>
<output>8</output>

<result>8</result>