Real Numbers

Algebra - Lesson 1 - Classifying Real Numbers
(08/20/12)



Real Numbers

Subsets of Real Numbers

• Natural Numbers - numbers to count things {1,2,3,4,...}
• Whole Numbers - natural numbers and 0{0,1,2,3,...}
• Integers - whole numbers and opposites of natural numbers {...,-2.-1,0,1,2,...}
• Rational Numbers - numbers that can be written as fraction or quotient a/b (a and b are integers, b not = 0)
• Irrational Numbers - numbers that can't be written as a/ b
• Real Numbers - rational and irrational numbers

Vocab

• Venn Diagram - shows relationship between sets (see image above)
• Set - collection of objects
• Empty Set (Null)
• Finite Set
• Infinite Set
• Intersection of Sets
• Union of Sets
• Closure - operation on any 2 numbers of a set is included in that set - Example - see set B 5+10=15 is included in set B, but 10+15=25 is not included, therefore, Set B is not closed
• Counter Example - proves a statement false