There is a book with a total of 900 pages, and the pages are numbered 1, 2, 3... Ask how many times the number "0" appears in the page number.
有一本书共900页，编上页码1、2、3…问数字"0"在页码中共出现多少次．
<gadget id="calculator">82 + 18 + 72</gadget>
<output>172</output>

<result>172</result>