adverb
a great many; ever so many
Emphasizes a large, indefinite number; often used in affirmative statements.
彼はいくつでも質問に答えた。
He answered a great many questions.
adverb
any number; as many as you like; no matter how many
Used with expressions like よい, 構わない, or in contexts of permission or indifference to quantity.
いくつでも好きなだけ取ってください。
Please take as many as you like.
いくつでも構いません。
Any number is fine.