In nummer theory, twa integers a an b are said tae be relatively prime, mutually prime, or coprime (an aw written co-prime) if the anerly positive integer (factor) that divides baith o them is 1. Consequently, ony prime nummer that divides ane daes nae divide the ither. This is equivalent tae thair greatest common divisor (gcd) being 1.
- Eaton, James S. Treatise on Arithmetic. 1872. Mey be dounlaidit frae: https://archive.org/details/atreatiseonarit05eatogoog
- Hardy & Wright 2008, p. 6