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8th Grade Slides

8th Grade Slides. Exponents. Exponents. Key Skill: Calculate values of expressions with positive and negative exponents. Quick Review. Exponent. Base. Exponent Review. Repeated multiplication:. Exponent Review. Any number to the first power is?. Exponent Review.

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8th Grade Slides

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  1. 8th Grade Slides Exponents

  2. Exponents • Key Skill: Calculate values of expressions with positive and negative exponents.

  3. Quick Review Exponent Base

  4. Exponent Review • Repeated multiplication:

  5. Exponent Review • Any number to the first power is?

  6. Exponent Review • Any number to the first power is itself • So • And

  7. Exponent Review • Any non-zero number to the power of 0 is?

  8. Exponent Review • Any non-zero number to the power of 0 is 1. • So, • and (assuming x does not = 0),

  9. Question • What is

  10. Question • What is • Is it the same as

  11. Odd and Even Exponents • Will a negative number raised to a power always be positive?

  12. Odd and Even Exponents • How do we know whether a negative number raised to a particular power will be positive or negative?

  13. Odd and Even Exponents • How do we know whether a negative number raised to a particular power will be positive or negative? Negative base with an odd exponent results in a NEGATIVE answer Negative base with an even exponent results in a POSITIVE answer

  14. Decimals and Fractions • Is this the same as

  15. Decimals and Fractions • Is this the same as No!

  16. Negative Exponents • Look at this progression of numbers: 33 = 32 = 31 = 30 = 3-1 = 3-2 = 3-3 =

  17. Negative Exponents • Look at this progression of numbers: 33 = 27 32 = 9 31 = 3 30 = 1 3-1 = 1/3 3-2 = 1/9 3-3 = 1/27

  18. Negative Exponents • Rule:

  19. Negative Exponents • The reverse is also true:

  20. Negative Exponents • We generally do NOT want negative exponents in our answer (unless we are using Scientific Notation). • We move bases with negative exponents to the denominator where they will turn positive. • If a negative exponent is found in a denominator, we move it to the numerator.

  21. Method Step 1: Take the RECIPROCAL of the base. What does RECIPROCAL MEAN? Step 2: The exponent moves with the base, but the negative sign in the exponent disappears.

  22. Examples

  23. Examples

  24. Exception • Numbers generally get LARGER when we square them. What kind of numbers get SMALLER when we square them?

  25. Exception • Numbers generally get LARGER when we square them. What kind of numbers get SMALLER when we square them? • Numbers between 0 and 1 (fractions and decimals)

  26. Classwork • Pages

  27. Exponent Laws • Key Skill: Apply the Laws of Exponents to simplify expressions.

  28. Exponents • Reminders: • Anything raised to the power of 1 is itself. • Any non-zero number raised to the power of 0 is 1. • When we see we use PEMDAS to determine what to do first. • In this case, raise ‘x’ to the 3rd power, THEN multiply by 4

  29. PEMDAS Parentheses ( ) Exponents 3 Multiplication x, Division ÷ Addition + Subtraction __

  30. Please Excuse My Dear Aunt Sally • Parentheses ( ) • Exponents 3 • Multiplication x, • Division ÷ • Addition + • Subtraction __

  31. Product Law of Exponents • How would we multiply:

  32. Product Law of Exponents • How would we multiply: • We could rewrite it as: (4 x 4 x 4) x (4 x 4)

  33. Product Law of Exponents • How would we multiply: • We could rewrite it as: (4 x 4 x 4) x (4 x 4) • Or with an exponent: • Note that we did NOT multiply the exponents, we ADDED them!

  34. Another Example • How would we multiply:

  35. Another Example • How would we multiply: • We would rewrite the equation as: • Or more simply as: 32 • Again, we ADDED the exponents

  36. Example with a variable • What is:

  37. Example with a variable • What is: • Rewrite as: • Or more simply as:

  38. Product Law of Exponents

  39. Contra-Example • Does the Product Law of Exponents apply here?

  40. Contra-Example • Does the Product Law of Exponents apply here? • No! We do NOT have a common base or a common exponent.

  41. Product Law of Exponents • What about:

  42. Product Law of Exponents • What about: • Does it matter what order we write the factors?

  43. Product Law of Exponents • What about: • Does it matter what order we write the factors? • How about:

  44. Product Law of Exponents • What about: • Does it matter what order we write the factors? • How about:

  45. More Examples

  46. More Examples

  47. The Other Product Law • How would we work with: • What’s different/what’s the same?

  48. The Other Product Law • How would we work with: • We can rewrite as: (4 x 4) x (3 x 3) • Or as (4 x 3) x (4 x 3) because order doesn’t matter when we multiply

  49. The Other Product Law • How would we work with: • We can rewrite as: (4 x 4) x (3 x 3) • Or as (4 x 3) x (4 x 3) because order doesn’t matter when we multiply • Now we can rewrite as

  50. The Other Product Law • How would we work with: • What’s different/what’s the same?

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