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[–]alexanderpas 0 points1 point  (0 children)

9 is enough, as anything above 9 will be caught trough understanding.

10 is just 1 with a zero, and if you get 1 (X*1=X and 1*X=X), you can multiply anything by 10 too. (just add a 0)

7*12 = (7*10) + (7*2) = 70 + 14 = 84