On Sat, 29 Jun 1996, Ronald A Ward wrote: <stuff deleted> > 66. In discussing place value, I am aware that many writers put off > discussing the teens in this context because of the way we "say" the teen > numbers. But I once saw an interesting approach [from Wayne Peterson of > the Seattle Public Schools, I believe] which though humorously presented > does have considerable merit. Note how we pronounce "40, 60, 70, 80, and > 90." To be consistent, we should say "twoty, threety, fivety" for "20, > 30, 50." Now note what that does for the teens: "13" becomes > "onety-three" for example. Makes much more sense to me from a place value > perspective. Comments? :)
Interesting, Ron. This reminds me of other place-value based ways of talking; for example, we say "twelve sixty-five" in reference to a certain number of dollars and a certain number of cents. And phrases like "fourscore and seven" used to be common. I wonder whether forty-five is an abbreviation of "four tens and five." Karen Dee?
If so, it might make sense to approach place value from the assumption that ontogeny recapitulates phylogeny: we (collectively) used to refer to a certain number as four tens and five; perhaps in writing this was shortened to 4T5; and the language evolved (as it so often does) from our common use of it. Thirteen (ten and three) and other teens (tens) probably have a good reason for being "backwards;" again, hearing from the historians on this would be helpful. As Ron says, it would probably be really good for kids' development of number sense to get them involved in the evolution of the terminology. (Bonus points for anyone who can explain eleven.)
Kreg A. Sherbine | To doubt everything or to believe Apollo Middle School | everything are two equally convenient Nashville, Tennessee | solutions; both dispense with the firstname.lastname@example.org | necessity of reflection. -H. Poincare