How do you read the summa symbol with no superscript and the Real numbers subscript? How do you read $\int_\mathbb R f(x) dx$? I'm doing continuous random variables in probability, for context, so the whole thing is:
$\int_\mathbb R f(x) dx = \int^{\infty}_{-\infty} f(x) dx = 1 $
And I get the idea that it's just saying that the total area under the curve is 1, but how do I say the first part in English? "The integral over all the real values in the domain of f?"

I may read $\int_\mathbb R f(x)\;dx$ as
"The integral over R, f of x d x"
I may say "reals" instead of R.  I may omit "of x d x".
