Rational and Irrational Numbers Write down anything you know about rational and irrational number.

Rational Numbers Any number that can be written as a ratio, or fraction. How can these numbers be written as fractions? 4.5, 12.6, 0.35, -7, 112, 3.333….. Rational numbers are part of the Real Number System. They include integers, whole numbers and natural numbers.

Real Number System Rational Numbers Integers Whole Numbers Natural Numbers Irrational Numbers

Rational numbers: fractions, mixed numbers, improper fractions, decimals, repeating decimals, integers, and whole numbers, square roots of perfect squares They can be positive or negative. ½, 3 ½, -4/5, , -5.4, -15, 100, 0, √100, √16, √400, …(can include bar over number). Integers: Positive numbers, their opposites (negatives) and zero …,-3, -2, -1, 0, 1, 2, 3, … Whole numbers: Counting numbers and zero 0, 1, 2, 3, 4, … Natural numbers: Counting numbers 1, 2, 3, 4,..

Irrational Numbers “Unreasonable” numbers They don’t make any sense. Numbers that are non-terminating and non-repeating Examples: Pi- π (never ends, never repeats) Square roots of non-perfect squares √2, √32, √17, 3√5, √18

Let’s Practice 1) Which number is rational? √121, √2, √6, √12, π 2) Which number is irrational? √81, √8, √16, √49, √0 3) Which number is irrational? ½, …, …, -18/5, √196

Label each number as rational or irrational. √18 √101 √64-5 2/3 -1/3 √ … √ … π0 √5√2

Which answer choice represents a rational expression? A) √16 √2 C) √8 √2 B) √15 √3 D) √12 √4

Which expression is irrational? A) 4 3/5 B) C) √169 D) √48

Which expression is irrational? A) B) C)√2 D)-3.234