How should expressions involving set membership be read in mathematical statements?

"One note about reading this notation that I found confusing at first. Sometimes the expression “a ∈ X” is pronounced “a is an element of X,” but other times it is read “a, which is an element of X”. This may seem like a subtle point, and I guess it is, but if you’re not ready for it it can be a extra stumbling block to understanding the math (which is the last thing we need). Take this hypothetical (but quite typical) excerpt from a mathematical proof: “Suppose k ∈ N < 10 . . .” If you read this as “Suppose k is a natural number is less than 10,” it’s ungrammatical. It really should be understood as “Suppose k (which is a natural number) is less than 10.” This is sometimes true of additional clauses as well. For instance, the phrase “Suppose k ∈ R > 0 is the x-coordinate of the first point” should be read “Suppose k, which is a real number greater than zero, is the x-coordinate of the first point.” I’ll leave you with a statement about numbers worth pondering and understanding: ∅ ⊂ N ⊂ Z ⊂ Q ⊂ R ⊂ Ω."