If a student/person is having trouble remembering something, it's because the data isn't presented to the brain in a way that can be handled efficiently. If a hook is put into place, then hard-to-remember stuff gets pulled out with the easy-to-remember stuff. The brain stores four hooks very well: pictures, patterns, rhymes and stories. Most memory courses only use one or two of the hooks at the same time but Midget Digits involves all four hooks, pictures and stories are obvious. The patterns are established with consistent story characters and loci (setting of stories). The rhymes come in to play with characters names or the short poems at the beginning of the book.

Example:
Eight Skate, Fine Nine, Baby Two-Goo. "With our numbers we can shine. Now to tickle Fine Nine."