math 5 simplifying fractions instructor: mrs. tew turner
TRANSCRIPT
Math Warm-up - ANSWER
Find all of the factors of 40. See if you can find all 8.
1, 2, 4, 5, 8, 10, 20, 40
Pause to work.
Vocabulary
Greatest Common Factor: The greatest number that is a factor of 2 or more given numbers.Example: 18=2 x 3 x 3
24=2 x 2 x 2 x3Find the prime numbers!Benchmark fraction: Common fractions used for estimating, such as ½, ¼, ⅓, ⅔, & ¾.
Vocabulary REVIEW
Multiple: the result of multiplyingtwo numbers. Prime: a number that can bedivided evenly only by 1 or itself.Composite: a number that can bedivided evenly by numbers otherthan 1 or itself.
REVIEW Equivalent FractionsConnection to Level 4 Math
Some fractions are written differently as in this picture, but they each
represent the same amount of pizza!
Fractions in Simplest Form
A fraction is in simplest form when its numerator and denominator have no common factor other than 1.Examples:½, ⅓, ⅔, ¼, ¾, ⅕, ⅜, ⅞
Fractions in Simplest Form
To write 12/20 in simplest form, find a common factor of the numerator and the denominator. Since 12 and 20 are even numbers, we know this fraction is NOT in simplest form. What do you know about EVEN numbers? They are divisible by 2, right?
Fractions in Simplest Form
12/20 in both the numerator and the denominator the factor of 2 is shared. 2 is a common factor. Divide both12 and 20 by 2.
12 ÷ 2 = 620 ÷ 2 10
Is this fraction 6/10 in simplest form?
No
12 ÷ 2 = 620 ÷ 2 10
Both 6 and 10 are even. We need to divide them by 2 again! 6 ÷ 2 = 310 ÷ 2 5
We need to change the fraction again until it cannot be divided any more?
Yes, since 3 and 5 share no more common factors.
Is 3/5 in simplest form?
Fractions in Simplest FormIf a number is a factor of two numbers, it is called a common factor.
The greatest common factor (GCF), of 2 numbers is the greatest number that is a factor of both numbers.4 was the greatest common factor for both 12 & 20. 2 is a factor but we still did NOT have simplest form until we divided it by 4.
Simplify the fraction. common factor = common
multiple
4 ÷ 2 = 2 10 2 5
3 (Is this fraction in simplest form?) 5 Can the numerator & denomInator
be divided by a whole number?
Simplest Form
YES
(It was not in simplest form as it could be divided by ‘2’ for both the numerator & denominator.)
NO
Greatest Common Factor
The greatest common factor (GCF), of 2 numbers: 20 & 3020: 1, 2, 4, 5, 10, 2030: 1, 2, 3, 5, 6, 10, 15, 30The GCF of 20 & 30 is 10. Or 10 is a multiple of both numbers.
Document Camera
Get your notebook
and pencil ready.
Make sure you
have the Lesson #
and date on your
page.
Simplest Form
Quick CheckSome of the following fractions
CANNOT be simplified. Simplify the ones you can.
1. 2. 3. 4.
In your Math Notebook
Explain why some cannot be simplified, while others can be.
Quick Check Answers
1. No2. No3. YES…8/22 = 4/11 (÷ by 2)4. Yes…14/28 = 2/4 (÷ by 7)
Suggested Explanation: #1 and #2 fractions can’t be simplified because they do not share factors other than 1.
ConclusionSimplifying fractions , also known as, reducing or putting into lowest terms, means to make the fraction as simple as possible. They are still the same or equivalent but written with a different fraction name, as ½ = 2/4.To simplify a fraction, divide the top and bottom by the highest number that can divide into both numbers exactly.