As the website says – “Sophia makes it easier than ever to flip your classroom with our free teacher tools for blended learning. Transform your classroom into an active learning environment with our groups, quizzes, and tutorials features. You can also track student progress every step of the way with our data and analytics. Additionally, we offer awesome ways to continue your professional development.”
This is one site that needs no introduction – videos on just about anything for just about anyone with special classroom tools as well
A great YouTube Channel by Robert Donley (@MathDoctorBob). It includes more than 700 videos in 15 different maths areas such as algebra, calculus, geometry and statistics.
There mightn’t be a huge number of videos in this channel but they are very slick, engaging and rigorous. They cover a range of mathematical concepts and are well suited for use in the secondary school.