Скачать или смотреть Set Theory 9th Std Session 02

Set Theory begun with a blast ! We learnt first how to find out if a description is really counting as a set, becuase it must be well defined enough and not ambiguous.
then we learnt basic set notation and how to write a set , its elements , how not to repeat elements more than once, how order is not important and did some simple examples
in finding if something was an element or not an element of a set and three types of forms in which sets can be represented : descriptive form, set builder notation form, and roster
or tabular form. then did some exercises from Ex 1.1 . dealt with different types of sets starting with null set or empty set or void set, finite set, infinite set, then equivalent sets, then
equal sets , then subsets, then proper subsets .