Desmos
https://www.desmos.com/
Desmos is an online graphing calculator. In Desmos, you can graph functions, plot data, evaluate equations, explore transformations, and much more! One of the best functions is that if you create an account, you can save and title all of your graphs to go back to at a later time. And the best part about Desmos is...it's free!
Khan Academy
https://www.khanacademy.org
Khan Academy is a nonprofit website that aims to provide a free, world-class education for anyone, anywhere. Khan Academy offers instructional videos over a wide-range of topics. Students are able to practice and/or learn at their own pace; being able to fill in the gaps in their knowledge, and accelerate their learning. Once again, what's the best thing about this website (besides the content quality)? ... That's right, it's free!
GeoGebra
https://www.geogebra.org/graphing
Need something a little more technical than Desmos? Here's your answer! GeoGebra is another graphing calculator for functions, geometry, algebra, calculus, statistics, and 3-D math. GeoGebra creates an environment for students to explore and experiment with mathematical activities; which is essential for their academic growth. Within this program you can find intersection points, line of best fit, angles, lengths, areas, and more! And what was that? Yes, it's free!
Math Games for kids
https://www.mathgames.com
Online math games are an excellent way to get kids involved in their mathematics lessons, interested in the content, and most importantly, practicing their skills! Math Games is a trusted website with an easy-to-navigate set-up. There are hundreds of selections of online games as well as worksheets, sorted by grade-level, skills, and standards! Want your students to think Math is fun? Here's a great place to start!
DeltaMath
https://www.deltamath.com
DeltaMath is an excellent tool for teachers to use to track and monitor students' independent progress. Topics are beautifully and logically organized and content is in accordance to mathematical standards. Teachers have the ability to look at individual students' progress, log in times, time spent on work, number of attempts, and submitted answers. On the student end, students are able to watch tutorial examples and can see step-by-step solutions before (or after) they try their own.
IXL Math
https://www.ixl.com
Like DeltaMath, IXL offers a useful tool to track and monitor students' progress. As it pairs with the k-12 curriculum, IXL acts as an excellent reinforcement tool for students' independent learning after lessons in class.