ずつ
Usage
The number/amount X+ずつ indicated that someone does something (or something happens) with X as the unit(e.g. the teacher teaches ten new kanji a week; the woman gave three chocolates to each child)。"per/a, at a time, each, (little) by (little)
Examples
私は毎日漢字を五つずつ覚えることにしている。
I want to study five Kanji per day, so that I can remember them.
みんなが同時に話さないで、一人ずつ順番話してください。
Please don't all talk at once; speak one at a time in turn.