With the loss of Jamboard, there comes the loss of some simple ways that it was used in the classroom and now teachers have to find a new way to do what they did before. (This is also why I say to never marry technology, but to date it, it is always a shorter term relationship.)
While there are many tools out there than can allow you to create a digital whiteboard space where you can draw or work out math problems, such as Figjam, there may be some who just want a very simple and quick option. Canva has a Whiteboard option that is as simple as it gets. You just create the Whiteboard file and then you can easily access the small amount of drawing tools. Upload a coordinate plane image or use one of the built-in options, and you can now graph out equations. Just use the background and work out math problems or physics problems, and then save the file and share with students. This is a simple way to use this tool but sometimes that is all you need.
Watch the video below to see how to use the Whiteboard option in Canva.