What it means
いくつ asks how many items or units there are, or how many someone does something with. It is commonly used before a verb and can refer to countable things without naming a counter. The answer is usually a number, sometimes with a counter such as 個 or つ.
Usage note
いくつ is mainly for things and general quantities. Use question words such as 何人 for people and 何歳 for age. おいくつですか is a polite expression that can ask someone's age or, depending on context, the number of something.
How to use it
りんごはいくつありますか。
How many apples are there?
クッキーをいくつ食べましたか。
How many cookies did you eat?
りんごはいくつある？
How many apples are there?
クッキーをいくつ食べた？
How many cookies did you eat?
Example sentences
冷蔵庫に卵はいくつありますか。
How many eggs are there in the refrigerator?
旅行にりんごをいくつ持って行きましたか。
How many apples did you take on the trip?
この箱に電池はいくつ入っていますか。
How many batteries are in this box?
図書館で本をいくつ借りましたか。
How many books did you borrow from the library?
教室