I thought it was the Arabs.
It's their fault that the symbol "4" is in the fourth place in the sequence.
2+2 should equal "5," if that means that 2+3 equals "4."
The sequence would have been 1, 2, 3, 5, 4, 6... if only the Arabs hadn't gotten to it first!
-PJ
If we are going to do pre-Arab math, then really, it’s II + II = IV.