I do math rotations in my classroom. (Hands down the best way to reach all the needs of my students) I do four rotations, Teacher Time, Lesson Work, Tech Time and Game Time. I teach 1:1 and one of top tips I would suggest is MIX THINGS UP! My third graders can get "bored" quickly... so I keep rotating my Tech Time websites. So these are approved and tested in my classroom daily!
FRONTROW. This website is common core aligned and you can assign a math concept to your students as well as they work on their independent levels. It differentiates without us, the teacher, having to do ANYTHING!!!
Ms. Idealistic insisted that Prodigy is the hottest thing in the wizard-math game realm. I was very skeptical about signing my kiddos up to battling math wizards with graphics circa 1986 Zelda. BUT MY KIDS BEG...I MEAN....LITERALLY BEG TO PLAY! As a teacher, you can set "battles" aka math challenges. I also suggest setting up a profile for yourself because my students love to "battle" me.
MANGA HIGH is my hands-down my favorite and the kids love it too! It is aligned with the common core state standards and it is very user friendly. It has fun math games and my kids enjoy it. They do have a Premium version but FREE option is what I use in my classroom.
TenMarks is a site for teachers and students. TenMarks allows teachers to differentiated with a click of a button. And they have a huge database of test questions, so making that last minute quiz/assessment is easy to do!