Rings

0:00:00 - Intro and definitions of a ring 0:09:21- Example 1 0:14:19 - Eamples 2, 3 and the general - case 0:23:53 - Example 4 0:35:50 - Commutative rings and general properties of rings 0:55:12 Subrings and examples 5 and 6 0:59:32 - Special rings, example 7 and units