Hi Thomas, > substract and subtract are both correct Where did you see that word? > "Now nonstandard and rare" Yeah, I'm with Russ. I found "sub-S-tract" in the 1913 Webster's Dictionary but no longer in Webster's Second from 1960. (Finally, those dusty volumes found some use.) I have never heard, or seen, that form of "sub-tract," but let's give others a chance to chime in. Kind regards, Felix Lechner