Few is languages specific, so the logic for it should live with the language. Another language might have a plural for 3-6 but you would then need another way

Few is languages specific, so the logic for it should live with the language. Another language might have a plural for 3-6 but you would then need another way to describe it. I've mentioned this in another comment, but I think a range would be better such as 2..4 or 3..6