How Many Days, What Day, Which Day
noun, expression
What day equals the fairly obvious translation "what day." But, it also means how many days.
なんにち
This is a jukugo word, which usually means on'yomi readings from the kanji, but 何 actually uses the kun'yomi reading here! And since 日 has two on'yomi readings, here's a mnemonic to help you remember this reading: How many days does it take you to bake a naan Nietzsche (なんにち)? It's not easy to make a Nietzsche entirely out of naan, so I wonder how many days it would take.
アルバイト、何日休むんですか。
How many days will you take off from your part-time job?
何日がいい？
What day's good for you?
エレベーターから何日出られなかったんですか。
How many days were you stuck in the elevator?