Multiplication Magic

Mental Math · Axiom Academy

A product that looks like paperwork usually isn't. The right shortcut turns it into two small steps — and this unit is a shelf full of them. Same answer, a fraction of the work Nobody who is quick at mental arithmetic does the way it was taught in school — four little multiplications, a carry, two rows and an addition. They do something much shorter. Multiplication is full of shortcuts like that, and they are not tricks in the con-artist sense: each one is ordinary arithmetic wearing a disguise, and every one of them can be explained. Watch done the long way first — all seven written steps of it. Then watch that whole stack fall in on itself and get replaced by two multiplications with nothing to add up. Same numbers, same answer, far less work. That is the whole promise of this unit: not faster grinding — less grinding. 23 and 27 are not special numbers. They are just a pair that starts with the same digit and whose last digits add to 10 — and every pair like that folds the same way. Slide the dials to build another one. The two small multiplications are always right there: the shared digit times the next number up, then the two last digits. It opens on , the pair the animation just took apart. Seven written steps down to three, for thirty-two different products — and this is only one shortcut of many. The 5-and-5 case belongs to squaring, and gets a lesson of its own. The shelf you're about to be handed

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