I am also the father of a 20-year-old son with severe, but verbal autism. I found a way help to match the number to the letters using alphanumeric character matching. It was found by placing Letters and numbers together it gave text or numeric values that he was able to understand and memorize the values together as one action. I created this book and started a parent of children with autism support group, to educate parents and family members that alphanumeric character matching may be helpful for your child. Every child with autism is different, not all autism is the same.