何(なん) + (Counter) + かSome, Several, A few

These patterns are similar in that both combine a counting expression with a particle. Number/Amount + は has a contrastive nuance, implying 'at least' that amount. For example, １０人は来ると思うけど ('I think at least 10 people will come.', implying the speaker is uncertain if any more will.). In contrast, なん + counter + か means 'a few (A)' or 'several (A)', e.g. 何人か 'a few people.'

なん + counter + か is a pattern that 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.' This is essentially the same as the question word + particle, or 誰か・どこか・誰も・どこも, structure, which is used in expressions such as 何か 'something', 誰か 'someone', and so forth.

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.')