1. Ch 2.1 Objective: To recognize different sets of numbers and to identify a domain.

2. Definitions Natural Number 1, 2, 3, 4, …… (all the numbers you would include if you were to count from 1 to infinity) Whole Number 0, 1, 2, 3, 4, ….. (all of the natural numbers and 0) Integer -2, -1, 0, 1, 2, ……All of the whole numbers including positive numbers, negative numbers, and zero. Keep in mind that fractions are not integers. Rational Number -2/7, -1/2, 0/3, 4/5, 3/1………Any number which can be written as a fraction. Irrational Number Any number which can NOT be written as a fraction (a non-terminating & non-repeating decimal) Real Number -2, -1, -1/2, 0, ½, 1, 2, ………All of the Integers plus all of the fractions in between the whole numbers. Note: there are a few exceptions to this but you will learn about these numbers later. Positive Number ½, 1, 2, 100, ………….A number greater than 0. In other words, if x > 0, then x is a positive number. Negative Number -1/2, -1, -2, -100, ………A number less than zero. In other words, if x < 0, then x is a negative number.

3. Real Numbers Rationals Irrationals Any number which can be written as a fraction Non-terminating and non- repeating decimals which can’t be written as fractions. Examples: 7 2.09

4. Real Numbers Rationals Irrationals Any number which can be written as a fraction Non-terminating and non- repeating decimals which can’t be written as fractions. Examples: 7 2.09

5. Sets of Numbers Reals RationalsIrrationals - any number which can be written as a fraction., 7, -0. 4 Fractions/Decimals Integers, -0. 32, - 2. 1 … -3, -2, -1, 0, 1, 2, 3... Negative IntegersWholes … -3, -2, -10, 1, 2, 3... Zero 0 Naturals 1, 2, 3... - non-terminating and non-repeating decimals

6. Make a Venn Diagram that displays the following sets of numbers: Reals, Rationals, Irrationals, Integers, Wholes, and Naturals. Naturals 1, 2, 3... Wholes 0 Integers -3 -19 Rationals -2. 65 Irrationals Reals

7. Naturals 1, 2, 3... Wholes 0 Integers -3 -19 Rationals -2. 65 Irrationals Reals Imaginary Numbers

8. Identify all of the sets to which each number belongs. (Reals, Rationals, Irrationals, Integers, Wholes, Naturals) 1) -6 2) 3) 14 4) 6 Integer, Rational, Real Rational, Real Natural, Whole, Integer, Rational, Real Irrational, Real

9. Identify all of the sets to which each number belongs. (Reals, Rationals, Irrationals, Integers, Wholes, Naturals) 1) 0 2) - 2.03 3) 4) Whole, Integer, Rational, Real Rational, Real Irrational, Real Integer, Rational, Real

10. Graphing Real Numbers on a Number Line Graph the following numbers on a number line. -4 -3 -2 -1 0 1 2 3 4

11. Domain- the set of values which may be meaningfully substituted for a given variable. Which set of numbers would best describe the variable? 1) Let x = the number of people at a meeting. D : x Naturals “ is a member of ” 2) Let y = your weight D : y Positive Reals 3) Let t = the low temperature in Alaska yesterday D : t Reals 4) Let n = the low recorded temperature in Alaska. D : n Integers