HCF and LCM Math Olympiad, I.S.I. Entrance and College Mathematics › Forums › Math Olympiad, I.S.I., C.M.I. Entrance › Number Theory › HCF and LCM Tagged: algebra This topic contains 1 reply, has 2 voices, and was last updated by Tarit Goswami 5 months, 1 week ago. Viewing 2 posts - 1 through 2 (of 2 total) Author Posts June 1, 2018 at 4:08 pm #21570 Pinaki BiswasParticipant If HCF(a,b)=1, then prove that LCM(a,b)=ab. June 7, 2018 at 11:02 pm #21578 Tarit GoswamiParticipant Well, we know from childhood that, gcd(a,b )*lcm(a,b)=ab. From here, as, gcd(a,b)=1 we will have lcm(a,b)=ab. This reply was modified 5 months, 1 week ago by Tarit Goswami. This reply was modified 5 months, 1 week ago by Tarit Goswami. Author Posts Viewing 2 posts - 1 through 2 (of 2 total) You must be logged in to reply to this topic.