Here each number has its own color. That way you can see the regular pattern. If you start on the left and move down the column, you get the first 10 numbers as usual. The advantage of seeing it in a rectangular array is that when you go across the top row, you also see the first ten numbers, but with 0's after them. I hoped this would be clear to him.The only problem is that, for whatever reason, the numbers from 11 to 19 do not follow the same convention as the numbers from 20 - 99. I don't know why. I was considering changing them for R's sake. I would call them "Ten - e - one", "Ten - e - two", etc. Then he would see the structure right away with the disadvantage that it is nonstandard. My wife S vetoed this. Oh well.
That brings up an interesting question (at least to me). Where do the words "Twenty", "Thirty", etc. come from. My initial uneducated guess is that they are shortened versions of "Two - ten" and "Three - ten". But I don't know. Does anyone know the answer to this?
