How do we pronounce E = mc²? This is a physics equation.
You read this as E equals M C squared, with the three letters pronounced as you would when reading the alphabet.
The "=" sign is read as "equals" or "is equal to", depending on your culture.
(In the latter case, "is equal to" is such a common phrase all through school that it's typically read as one word: "izziqualtu".)
The "c2" could rarely be "c [raised] to the power of 2", but is almost always "c squared" (or "c square").
Thus, "ee equals em see square[d]" or "e is equal to em see square[d]".
Alternatively, one could say
Energy is the mass times the square of the speed of light in a vacuum.
If you are so inclined.
If you listen to this audio clip of Albert Einstein speaking in 1947, you can hear him say it as "E is equal M C square" (with letters as ee, em, see).
But nowadays it's normally pronounced as Jasper Loy answered: E equals M C squared.
Very simple you just go on speaking each word and symbol as they are. So that makes it : "E is equal to M C Square "