This paper (actually three short articles) describes Louis Benezet's now-80-year-old experiment to delay the teaching of formal arithmetic until grade 7. This article has been the subject of much debate over the years, and (as far as I know) there has been no real modern equivalent; I'm interested to know: what do you all think?
In the spirit of open discussion, I'll hold off on giving my own opinion until down in the comments; hopefully this will let those who are not familiar with this article read it relatively free of bias.