Mingming reads an extra-curricular book, 17 pages on the first day, 23 pages on the second day, and 20 pages on the third day. How many pages did he read in total?
明明读一本课外书，第一天读17页，第二天读23页，第三天读20页，他一共读了多少页．
<gadget id="calculator">17 + 23 + 20</gadget>
<output>60</output>

<result>60</result>