A book has 420 pages in total. I read 115 pages on the first day and 89 pages on the second day. How many pages are left?
一本书共有420页，第一天看了115页，第二天看了89页，还剩几页没有看完？
<gadget id="calculator">420 - 115 - 89</gadget>
<output>216</output>

<result>216</result>