I〔数学で〕the greatest common divisor [denominator] ((略 G.C.D.))
8,・20,・40の最大公約数は4である
The greatest common divisor of 8, 20 and 40 is 4.
II〔違った意見の間の共通点〕
反戦論は左右両派の主張の最大公約数だった
The only common ground shared by the left and right wings was a belief in pacifism./The only thing the left and right wings had in common was anti-war feeling.