Fetching details from the dictionary...

subject; theme; issue; matter
homework; assignment
task; challenge; problem; question
今週の課題を終わらせた。
I finished this week's assignment.
夏休みの課題を早めに終わらせたいと思う。
I want to finish my summer vacation homework early.
この課題を解決するには時間がかかります。
It takes time to solve this problem.