Websites come and go — but the ones that are truly useful stick around for the long term. For students, having a few go-tos in your back pocket whenever you need to exercise some math muscles, build vocabulary, practice analytical skills, or do research is a time-saver (and sometimes a lifesaver!). What kinds of sites are bookmark-worthy? Ones that offer solid, supplementary information, adapt to your kid’s level, provide fun practice instead of drill-and-kill, and show videos to explain complex concepts. Class after class, semester after semester, these 10 sites are the ones you’ll come back to. So bookmark them — you’ll start learning a lot faster.

10 Websites All Kids Should Bookmark