Xiao Ming read 20% of a book on the first day, 60 pages on the second day, and left 120 pages unread. How many pages are there in total?
一本书小明第一天看了20%，第二天看了60页，还剩120页没看，这本书一共有多少页？
<gadget id="calculator">60 + 120</gadget>
<output>180</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">180 / (4/5)</gadget>
<output>225</output>

<result>225</result>