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what
how many
many; a lot of
several; a few; some
「何」 has another reading with different meanings.
何なんでそんなことしたの?
Why did you do something like that?
兄弟きょうだいは何なん人にんいるんだよ。
So how many siblings do you have?
何なんと言えいえばいいか分からわからない。
I don't know what to say.