OK, this is genius how to teach children multiplication. Use your "hand calculator" to figure 8 and 9 multiplication tables. Where was this when I was in school? (Also, this is a crazy long video for such a simple concept.
Older children can use this to learn the table finger trick. Fold down finger you're multiplying 9 by; count how many fingers to the left of that folded down finger & how many to the right of that finger That's your answer, 6 x 9 = 54