Although not directly related with the book, I would like to recommend, as an introduction to basic arithmetic, the youtube videos NJ Wilderberg. He has very w

Although not directly related with the book, I would like to recommend, as an introduction to basic arithmetic, the youtube videos NJ Wilderberg. He has very weird and non-standard ideas that you should not take too seriously, specially if you get into his videos on more advanced stuff, but his way of teaching basic arithmetic is certainly inspiring.