This is what Wasatch school district uses in their 1:1 laptop initiative. The teacher can see all the kids' screens, and project any one that they want, and message the kids too.
This is the software they use in Wasatch school district in their 1:1 laptop initiative. I saw it in action, and it looked great! It's like Khan Academy with video and exercises with prompts, but it's more refined and integrated with the math curriculum.