A book, after reading for a few days, there are 160 pages left, which is 20 pages less than this book (9/10). How many pages are there in this book?
一本书，看了几天后还剩160页没看，剩下的页数比这本书的(9/10)少20页．这本书一共多少页？
<gadget id="calculator">160 + 20</gadget>
<output>180</output>

<gadget id="calculator">9 / 10</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">180 / (9/10)</gadget>
<output>200</output>

<result>200</result>