> When I was a student (must have been about 1980) there was an article
> in New Scientist proposing a decimal system but with digits representing
> -4, -3, -2, -1, 0, 1, 2, 3, 4, 5 so that 16 would have been written as
> "2 (-4) ". The benefit is that multiplication tables are much fewer and
> simpler. I can't recall whether a history was given for this system.
Cedric. A. B. Smith was probably the author of the article you read.
He was one of the four students of Trinity College Cambridge who wrote
the famous paper on cutting squares into unequal squares, and then I
think taught at University College London and headed the Galton Institute.
He's written a book on genetics in which he introduced and used his
system, the negative digits being the upside-down versions of the
positive ones. He allows -5 as well as +5, and has a different way
of restoring the uniqueness.
John Conway