I’m such a fan of your books that I just had to reply. I have both the addition/subtraction and multiplication book (found them online) and I’m dearly hoping that you’re working on a division version! I’m a parent who is supplementing my son’s math education at public school with your books. He has a terrific school and teachers, but has ADD and math is his least preferred activity so it’s a challenge!  I’m working with him on just the basic math facts so that his learning in other math areas in school is supported by a solid foundation. The schools really don’t have the time to thoroughly address basic math facts, and I’m happy to take on the task particularly when I have terrific tools like yours to use.