For those who have read and heard Keith Devlin, he is pretty close with Jo Boaler who you may also have heard about. Keith Devlin, you will recall, writes a column called Devlin’s Angle in MAA and also is known as “that math guy” at NPR.
He made a big name for himself some years ago when he claimed that multiplication “Ain’t no repeated addition”.
Well, yes, in formal, higher level mathematics, there is a general definition of multiplication that must meet several conditions. Technically, it is a function which maps two objects (numbers, functions, even shapes) from a set, into one object, (e.g., f(2,4) = 8 ) and the function is commutative, associative, distributive, and has an identify function called “1” in which a*1 = a.
What he seems to miss is that this general function does in fact include repeated addition as a means of informing the…
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