MathGrade 4 Mrs. Ennis Factors and Multiples Lesson Nine
Factors and Multiples
Vocabulary • Product – the answer to a multiplication problem. • Times – multiply. • Factor-the numbers you multiply together to get another number
Vocabulary • Multiple-the result of multiplying two numbers • Prime-a number that can be divided evenly only by 1 or itself. • Composite-a number that can be divided evenly by numbers other than 1 or itself.
Multiples • A multiple is formed by multiplying a given number by the counting numbers. • The counting numbers are 1, 2, 3, 4, 5, 6, etc.
Example: List the multiples of 4: • 4 x 1 = 4 • 4 x 2 = 8 • 4 x 3 = 12 • 4 x 4 = 16 • 4 x 5 = 20 • 4 x 6 = 24 So, the multiples of 4 are 4, 8, 12, 16, 20, 24, 28, etc. Counting Numbers
What are the first five multiples of 13? 13, 26, 39, 52, 65 13 x 1 =13 13 x 2 = 26 13 x 3 = 39 13 x 4 = 52 13 x 5 = 65
Find the Missing Multiples 24 30 • 6, 12, 18, ____, ____ • ___, 6, 9, 12, ____, ____, 21 • ___, 24, 36, 48, 60, ____ 15 18 3 12 72
Factors • Factors are the numbers you multiply together to get a product. • For example, the product 24 has several factors. • 24 = 1 x 24 • 24 = 2 x 12 • 24 = 3 x 8 • 24 = 4 x 6 • SO, the factors are 1, 2, 3, 4, 6, 8, 12, 24
Finding Factors • Start with 1 x the number. • Try 2, 3, 4, etc. • When you repeat your factors, cross out the repeat - you’re done at this point. • If you get doubles (such as 4 x 4), then you’re done. Repeats or doubles let you know you’re done.
What are the factors of 16? 1 x 16 2 x 8 3 x ?? 3 is not a factor, so cross it out 4 x 4 doubles = done The factors of 16 are 1,2,4,8,16
What are the factors of 18? 1 x 18 The factors are 1,2,3,6,9,18 2 x 9 3 x 6 4 x ?? 5 x ?? 6 x 3 Repeat! Cross it out! We’re done!
What are the factors of 7? 1 x 7 2 x ?? The only factors of 7 are 1,7 This means 7 is a prime number. 3 x ?? 4 x ?? 5 x ?? 6 x ?? This works, but it is a repeat. 7 x 1
Prime numbers are numbers that only have two factors: one, and the number itself. EXAMPLES: 3, 5, 7, 11, 31 Composite numbers have more than two factors. EXAMPLES: 6, 18, 30, 100 Prime and Composite Numbers
Watch this! Prime or Composite?
Online Practice • Factor Feeder (eating factors) • Fruit Shoot (prime or composite)
Math Fun A man wanted to get into his work building, but he had forgotten his code. However, he did remember five clues. These are what those clues were:The fifth number plus the third number equals 14. The fourth number is one more than the second number. The first number is one less than twice the second number. The second number plus the third number equals 10. The sum of all five numbers is 30.What were the five numbers and in what order?
Answer: 7, 4, 6, 5, 8
Resources: http://math.pppst.com/multiplication.html http://aaamath.com/B/g4_38gx1.htm http://www.braingle.com/brainteasers/teaser.php?op=2;id=21087;comm=0 http://mathlearnnc.sharpschool.com/UserFiles/Servers/Server_4507209/File/Instructional%20Resources/G4WW1-4.pdf http://www.multiplication.com/interactive_games.htm http://www.gamequarium.com/multiplication.html
Resources: cuip.uchicago.edu/~jhammond/math/4.1.ppt http://mathlearnnc.sharpschool.com/UserFiles/Servers/Server_4507209/File/Instructional%20Resources/G4WW1-4.pdf http://studyjams.scholastic.com/studyjams/jams/math/multiplication-division/prime-composite-numbers.htm http://www.braingle.com/brainteasers/teaser.php?op=2;id=21087;comm=0
http://hoodamath.com/games/factorfeeder.php http://www.sheppardsoftware.com/mathgames/numbers/fruit_shoot_prime.htm
