SOLVED: Show that: 1) N-1,-2,-3 is a denumerable set 2) N∪-1,-2,-3 is a countable set 3) 5,6,7, ... is an infinite set N is the set of odd positive integer numbers.
Countable set - YouTube
Lec # 5
Uncountable Sets - courses - MIT
SOLUTION: Countable uncountable set notes for msc maths 2 - Studypool
9.2: Countable Sets - Mathematics LibreTexts
Countable Sets, Countably Infinite Sets and Uncountable Sets- DEFINITION WITH EXAMPLES - YouTube