We have seen that complex numbers came to be viewed as ordered pairs of real numbers. That is, a complex number z is defined to be z = (x, y) . The reason we say ordered pair is because we are thinking of a point in the plane. The point (2, 3), for example, is not the same as (3, 2). The order in which we write x and y in the equation makes a difference. Clearly, then, two complex numbers are equal if and only if their x coordinates are equal and their y coordinates are equal. In other words, (x, y) = (u, v) iff x = u and y = v .