The only 1 of 3 by 3 that adds to 15 diagonally Posted on March 13, 2017 by Kenneth Udut Leave a comment The only 1 of 3 by 3 that adds to 15 diagonally [responsivevoice_button voice="US English Male"] Leave a comment Cancel reply Your email address will not be published. Required fields are marked *Comment Name * Email * Website Save my name, email, and website in this browser for the next time I comment. four × = 20 Leave a Reply