Cartesian product

In mathematics, sets can be used to make new sets. Suppose we have two sets A and B. Then the Cartesian product of A with B is written as A × B and is the set of all ordered pairs whose first element is a member of A and whose second element is a member of B.

For example, let A = {1, 2, 3} and B = {a, b}. Then:

$A\times B=\{(1,a),(1,b),(2,a),(2,b),(3,a),(3,b)\}$