A story book has 330 pages in total. I read 160 pages on the first day and 130 pages on the second day. How many pages are left?
一本故事书共有330页，第一天看了160页，第二天看了130页，还剩多少页没看？
<gadget id="calculator">160 + 130</gadget>
<output>290</output>

<gadget id="calculator">330 - 290</gadget>
<output>40</output>

<result>40</result>