[6ren]

  At PARC we had a slogan: "Point of view is worth 80 IQ points." It was based on a
  few things from the past like how smart you had to be in Roman times to multiply two
  numbers together; only geniuses did it. We haven't gotten any smarter, we've just
  changed our representation system. We think better generally by inventing better
  representations; that's something that we as computer scientists recognize as one of
  the main things that we try to do.

Alan Kay http://billkerr2.blogspot.com.au/2006/12/point-of-view-is-wo...

[taybin]

According to this, multiplication wasn't so bad: http://turner.faculty.swau.edu/mathematics/materialslibrary/...

[btilly]

Actually real Romans did multiplication on an abacus. Reading from Roman numerals to/from an abacus is an incredibly natural operation.

In Europe the disappearance of abacuses was directly tied to the rise of Arabic notation.

[e12e]

Without a table? Just from memory? I think I'd prefer decimal.