prefix word

For prefix words on octo is combining form in nouns, adj, adv,eight;having eight:-eg octagon(geometry); octave (eight notes on a scale); octavo (size of book page into eight leaves), octopus (sea creature eight long arms for food.) (also the MTR travelling issued card.) etc. for student's use.
For prefix words on multi is combining form in noun and adj for more than one; many:-eg -multicoloured, a multimillionaire, a multimillion, a multi-ethnic society; multi-access, multi-channel, multi-coloured, multi-cultural, multi-lateral negotiations, multi-lingual, a multi-media approach to learning for students , multiple-choice is showing several possible answers from which student must choose the correct one. etc.

im

mal-
e.g. malnutrition