expression, godan verb (-ru)
have one's turn; be on duty
Used when it is someone's turn to do something, often in a rotating schedule or queue. The phrase implies a sense of responsibility or obligation for that turn.
今日は私が掃除の番に当たっている。
Today it's my turn to do the cleaning.
次は誰の番に当たりますか。
Whose turn is it next?