Example

Let R = Z/4Z[X]/({2, X²}). Its elements are (represented by)

0, 1, X, X + 1.

We write down the multiplication table of this ring.

×	0	1	X	X + 1
0	0	0	0	0
1	0	1	X	X + 1
X	0	X	0	X
X + 1	0	X + 1	X	1