There seems to be a consistent problem with mathematics education, especially in the US. It drives me nuts.
I had a conversation with DD's principal the other day. We were talking about nitpicking petty things in DD's math homework. An example I gave him in a letter I wrote was that she was marked wrong for writing
809 as "eight hundred and nine" instead of "eight hundred, nine." My overall argument was that she needs challenging work in order to develop well and that she won't get there worrying about "eight hundred, nine."
The principal told me that in fact "eight hundred, nine" is the correct way to write it (according to Wolfram Mathworld it actually has to be written without that comma, and DD's math teacher picks on that level of "error"). Regardless, he really didn't seem to understand either the real problem with my DD, the point of writing out the word names of the numbers, or just how picayune this was.
IMO, most of our elementary (maybe middle school, too?) educators simply don't have a real understanding of mathematics and so substitute this kind of thing (as noted in the thread about Liping Ma's book;
here's a summary of her findings).
