I disagree, Nigel. I can't see anything wrong with that. Like you, I imagine, I chanted my times tables in primary school ad nauseam: one times two is two, two times two is four, three times two is six (I'll let you argue the "is/are" there, but I'm sticking with "is")... I'm pretty sure that the expression "times tables" and the verb "to times" are natural derivatives of that. And there isn't much point arguing against them: their usage is so common that you'd really have to admit that they're standard English. I rather like both, actually. I like the informality, and I'm sure that they are friendlier means of expression to small children for teachers to use. If you don't like them, I fear you'll have to consider it another battle lost...