What is the operator priority in set theory?

Say I have three arbitrary sets $A,B,C$.

Which statement is true ?

$A \times B \cup C = (A \times B) \cup C$ $\quad$ or $\quad$ $A \times B \cup C = A \times (B \cup C)$

And the same question for Union and Intersection.

Which statement is true ?

$A \cap B \cup C = (A \cap B) \cup C$ $\quad$ or $\quad$ $A \cap B \cup C = A \cap (B \cup C)$

• I usually just use parenthesis. Sometimes it's clear from context. – Asaf Karagila Jan 19 '15 at 21:30

Since both $\cap$ and $\times$ are generally viewed as "multiplication-like" and $\cup$ is "addition-like", most readers would probably, if they had to choose, interpret your expressions as $(A\times B)\cup C$ and $(A\cap B)\cup C$.