1. Rational and irrational numbers
Math 8 / Lesson 1.1
Unit 1: real numbers, exponents, and scientific notation
Mrs. Pellizzer

2. Objective
SWBT identify and explain the differences between rational and irrational numbers, as well as understand that every number has a decimal expansion.
CA CC 8.NS.1, 8.NS.2, 8.EE.2

3. Essential question
How do you rewrite rational numbers and decimals, and take square roots and cube roots?

4. Rational and irrational numbers
Numbers that cannot be written as a/b, where a and b are integers and b is NOT 0
Any number that can be written as a ratio in the form a/b, where a and b are integers and b is NOT 0

5. Let’s play number matchmaker
RATIONAL NUMBERS
(see ed slide to move #s)
IRRATIONAL NUMBERS
(see ed slide to move #s)

6. Rational numbers as decimals
Terminating Decimal
Repeating Decimal
0.5
1.5
19.99
FINITE NUMBER OF DIGITS (THE DIGITS END AT SOME POINT)
0.91
0.2
ONE OR MORE DIGITS THAT REPEAT FOREVER

7. Understanding check – complete the following

8. BUT WHY? Square Root Basics PERFECT SQUARES
36 81
10,000 4
Square Root Basics
the math: the square root of a positive number p is x if x2 = p
BUT WHY?
NON PERFECT SQUARES
x2 = 144
√x2 = √144
x = √144
x =
7 10 1,
56 87

9. Please hit the play button and watch this video on cube roots
Please hit the play button and watch this video on cube roots. Don’t worry if it is confusing. This is just an introduction!
CUBE ROOT BASICS
the math: the cube root of a positive number p is x if x3 = p

10. Exit ticket
Cliff Notes Express TASK: Using an index card, prepare a “cheat sheet” covering today’s topics. WHAT: Must have headings – what were the main topics covered today? HOW: You can use bullets, pictures, numbers, & symbols. Cheat sheets should help you quickly remember key details. Partner or independent work ok. WHEN: Now! Due at the end of the period. Place in the purple basket as you leave. CHAMPS: Independent or Partner Work / Voice Level 2 Max