几 + Measure Word + Noun
The question word 几 (jǐ) means "how many" or "several" and is used to ask about a small, countable number. It is placed before a measure word and noun to form a question. For example, 几天 means "how many days" or "a few days."
你家有几口人?
Nǐ jiā yǒu jǐ kǒu rén?
How many people are in your family?
这个星期你上了几节课?
Zhège xīngqī nǐ shàng le jǐ jié kè?
How many classes did you have this week?
你去过几个国家?
Nǐ qù guò jǐ gè guójiā?
How many countries have you been to?