J. Crabtree says: >Joe to me simpler means easier to understand, do and get correct. Should we accept sloppy, illogical, incomplete and simplistic aspects of arithmetic or make it better? Numbers exist only to make our world simpler and lives happier. So do we.
This only makes me more unsure of whether you really want to simplify arithmetic per se or rather, the teaching of it. In addition to talking about 0,1,..9, +, -, /, *, =, why not describe in everyday terms how this hypothetical future person with the clearer understanding of numbers is going to benefit from it? Then that picture might help guide how to get there.