几

几 (jǐ) does two related jobs. As a question word, it asks 'how many' when the expected answer is a small number — usually under ten. 几点？ asks 'what time?' (literally 'how many o'clock'), 几个人？ asks 'how many people?' (assuming a few). For larger or unknown quantities, use 多少 (duōshao) instead. As a non-question word, 几 means 'a few / several': 几个朋友 means 'a few friends.' Crucially, 几 ALWAYS takes a measure word: 几个人 (how many people), 几本书 (how many books), 几岁 (how old, for a small child) — never 几人 or 几书. This is the opposite of 多少, which can drop the measure word. Asking a small child their age uses 几岁; an adult uses 多大.

Memory hook: 几 looks like a small bench — small numbers fit on a small bench.