Xiao Ming reads a 600-page book. On the first day, Xiao Ming reads 135 pages. On the second day, Xiao Ming reads another 165 pages. How many pages are left?
小明看一本600页的书，第一天小明读了135页，第二天小明又读了165页，还剩多少页没读？
<gadget id="calculator">135 + 165</gadget>
<output>300</output>

<gadget id="calculator">600 - 300</gadget>
<output>300</output>

<result>300</result>