Factors, Multiples, prime, & composite numbers, oh my!! Mrs. Everett 4th grade math

4.M.OA.B.04 I CAN FIND ALL THE FACTOR PAIRS, MULTIPLES, PRIME NUMBERS, AND COMPOSITE NUMBER FOR WHOLE NUMBER UP TO 100.

Essential questions What is a factor? How do I determine the factors of a number? What is a multiple? How do I determine the multiples of a number? What is a prime number? How do I determine a number is a prime number? What is a composite number? How do I determine a number is a composite number?

Vocabulary Factors are numbers that are multiplied. Multiples are the product of a given whole number and another whole number. A prime number cannot be divided by any other number other than 1 and itself. A composite number can be divided by other numbers besides 1 and itself.

Factors are numbers that are multiplied 8 X 8 = 64

What does “Find the factors” mean? …find all the numbers you can multiply together to get that number as the product.

EVERY number greater than 1 has the number 1 and itself as a factor.

Always write factors from least to greatest. What are the factors of 27? Remember, you are being asked to find all the numbers that can be multiplied together to get the answer 27. 27: 1 X 27 3 X 9 HINT: Always write factors from least to greatest. 1, 3, 9, 27

practice Find the factors: 18 24 21 52

Factors that two or more numbers have in common Common Factors What does COMMON mean? What does FACTORS mean? So….. COMMON FACTORS are: Factors that two or more numbers have in common

What are the common factors of 16 and 24? 1 X 16 2 X 8 4 X 4 24 1 X 24 2 X 12 3 X 8 4 X 6 Hint: Once you repeat a number you’re done!! 16: 1, 2, 4, 8, 16 24: 1, 2, 3, 4, 6, 8, 12, 24 Common Factors: 1, 2, 4, 8

Practice What are the common factors of: 6 & 9 24 & 48 25 & 45

Greatest Common Factor The greatest factor that both numbers have in common. GCF = Greatest Common Factor

Find the GCF 9 1 x 9 3 x 3 9 : 1,3,9 12 1 x 12 2 x 6 3 x 4 12: 1,2,3,4,6,12

Practice Find the GCF: 12 & 26 9 & 21

White board Practice List the factors: 36 18 27 List the common factors: 18, 22 52, 36 14, 9 List the GCF: 25, 40 30, 42

Multiples A multiple is the product of a given whole number and another whole number. 4: 4, 8, 12, 16, 20, 24…

Multiples form a skip counting pattern! 5: 5, 10, 15, 20, 25, 30…

List the multiples of 7 up to 42 7: 7, 14, 21, 28, 35, 42…

Example: Is 108 a multiple of 6? You use the INVERSE OPERATION of multiplication to see if a specific number is a multiple of the given number. Example: Is 108 a multiple of 6?

A multiple that 2 or more numbers have in common. Common Multiple A multiple that 2 or more numbers have in common. Example: Find the first 3 common multiples of 3 and 6. CM: 6, 12, 18 3: 3, 6, 9, 12, 15, 18… 6: 6, 12, 18, 24, 30, 36…

Is 36 a common multiple of 6 and 9? What strategy would you use? That’s Right! Division 36 ÷ 6= ? 36 ÷ 9=? Yes! 36 is a common multiple of 6 and 9.

Practice 1. Is 42 a common multiple of 6 and 9? List 10 multiples of each number and circle the common multiples. 2. 3 and 6 3. 4 and 12 4. 2 and 5

Least Common Multiple The smallest multiple that 2 or more numbers have in common. LCM = Least Common Multiple Example: Find least common multiples of 6 and 8. LCM: 24 6: 6, 12, 18, 24, 30, 36… 8: 8, 16, 24, 32, 40, 48…

White board Practice List the first 5 multiples of each number. 2 4 3. Name the LCM of the following numbers: 20 and 5 4. How many common multiples less than 50 do 8 and 9 have? Name them.

Prime Numbers A prime number cannot be divided by any other number but 1 and itself! 13 ÷ 1 = 13 13 x 1 = 13 Is there anything they can be multiplied together to make 13?

Therefore 13 is a prime number! NO! Therefore 13 is a prime number! Can you think of some other prime numbers?

Composite Numbers A composite number can be divided by any other number besides 1 and itself! 24 ÷ 1 = 24 24 ÷ 6 = 4 24 ÷ 2 = 12 24 ÷ 4 = 6 24 ÷ 12 = 2 24 is a composite number

Practice Think about it Think of 2 composite numbers. Turn to your neighbor and share those numbers and explain why they are composite numbers. Think about it Are there more prime numbers or composite numbers? WHY? Turn to your neighbor and share those numbers and explain why they are composite numbers.