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

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

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

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

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

Rational numbers as decimals Terminating Decimal Repeating Decimal 0.5 0.062599876 1.5 19.99 FINITE NUMBER OF DIGITS (THE DIGITS END AT SOME POINT) 0.91919191919191919191919 0.22222222222222222222222 0.91 0.2 ONE OR MORE DIGITS THAT REPEAT FOREVER

Understanding check – complete the following

BUT WHY? Square Root Basics PERFECT SQUARES 36 81 81 100 10,000 4 64 121 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 = 12 7 10 123 99 1,999 13 56 87

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

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