University of California, San Diego: Edward Bender and S. Williamson's "Sets, Equivalence and Order: Sets and Functions"
One last time, look over the above reading. Now study the product of sets defined on page SF-2, just before the section titled "Set Properties and Proofs." The Cartesian Product, A x B = {(a, b) : a ∈ A and b ∈ B}, is referred to as the set of ordered pairs of A and B. Clearly, it is analogous to multiplication of numbers.