x ∈ R can be translated as "The number x belongs to the set of the real numbers"
What does this mean?
I assume that what you have is:
" x ∈ R"
First:
The symbol ∈ means "belongs", so we can rewrite this as:
"x belongs to R"
Then, R is the notation used for the real number set, and x is the general variable for a number, then the statament can be written as:
"The number x belongs to the set of the real numbers"