You can turn on Math Solver feature on-demand now

 Make sure you are at least on Edge version 91.0.831.0 (Official build) canary (64-bit)

and then enable this new flag: edge://flags/#edge-math-solver

You can learn more about Math Solver feature here:

https://techcommunity.microsoft.com/t5/articles/learn-how-to-solve-math-problems-with-math-solver-in-microsoft/m-p/2195689