Further to my submission that the names of the numbers are a unique designation with no duplication, I should have specified that the name is written in longhand, so that the line is contiguous. Thus the "squiggle" in longhand of "twentyone" would be a unique squiggle. Although the last three letters are identical to the last three of "thityone", this is no different from saying that the lower half of the squiggle "3" is the same as the lower half of "5", yet we consider these to be different.
Further to my submission that the names of the numbers are a unique designation with no duplication, I should have specified that the name is written in longhand, so that the line is contiguous. Thus the "squiggle" in longhand of "twentyone" would be a unique squiggle. Although the last three letters are identical to the last three of "thityone", this is no different from saying that the lower half of the squiggle "3" is the same as the lower half of "5", yet we consider these to be different.