World Book eBooks contains over 30 math eBooks.  Simply open World Book eBooks, scroll down to the section marked as math, and click view all to see the full list of math eBooks.  Click the encircled letter i in the lower right corner of each book's thumbnail image to go to the information page.  The information page provides a direct link to that particular eBook that can be uploaded to Schoology.  World Book Bbooks must be read using the reader that is built into the database.

SIRS Discoverer provides over 25 math eBooks.  The math eBooks are listed on the page for Science-related non-fiction eBooks.  The easiest way to find the SIRS math eBooks is to press control and the letter f and search for the word Math on the page.  SIRS eBooks can be accessed by downloading the PDF or using the direct link (which can be accessed via the browser or via email).  Those using the direct link can view the eBook using the built in reader for SIRS.