Number + もEmphasis, As ~ as, Not even

Number + も emphasizes a large quantity, like 'as many as (A)' or 'a whole (A)' in English. In contrast, Number + しか〜ない emphasizes a small quantity. For example, おにぎりを３個も食べた ('I ate three whole rice balls.') vs. おにぎり１個しか食べなかった ('I only ate one rice ball.').

Both forms emphasize quantity, but with contrasting nuance. Number/Amount + は implies 'at least' that amount, with a contrastive tone. For example, ３０分はかかると思うけど ('I think it'll take at least 30 minutes.', implying that it won't be less, but might be more.). In contrast, Number + も emphasizes the amount as if the speaker believes it is a lot, e.g., ３０分もかかった ('It took thirty whole minutes.').

These patterns are similar in that both combine a counting expression with a particle. なん + counter + か combines the question word 何 (なん or なに) with a counter to mean 'a few (A)' or 'some amount of (A)', for example 何人か 'a few people.' In contrast, Number + も emphasizes that the number is large, e.g. １０００人も来た ('A whole 1000 people came.')