Фоменко Т. Н. - Математический анализ. Часть 1 - Лекция 2

The lecture begins at 00:00:10 with an introduction, followed by a discussion of bounded and unbounded sets of real numbers, supremum and infimum at 00:02:44, a theorem on the existence of supremum and infimum at 00:22:59, approximation of real numbers by rationals at 01:06:32, and properties of comparison, addition, and multiplication of rational numbers at 01:22:46.