Prime/Composite Numbers
Is 3 a Prime Number? Why?
Yes, it's only factor pair is 1 and 3.
What is a factor of 12? You cannot choose 1.
3, 4, or 12
What is ONE way to find a multiple of a number?
Skip count up by the number
OR
List the multiplication problems and answers.
I have 25 cards and need to divide them among my 5 friends. How many cards will each friend get?
5 cards.
True or False: 12 is a multiple of 4.
TRUE; 4 x 3 = 12
Is 16 a composite number? Why?
Yes, it has two sets of factor pairs, 1 and 16 and 4 and 4.
What is a factor of 16? Do not choose 1.
4 or 16
What is one multiple of 8 besides 8.
16, 24, 32, 40, 48...
I have 5 tables each with 4 chairs. How many chairs do I have total?
20 Chairs.
True or False: 33 is a composite number.
True!: 1 x 33 and 11 x 3 are the factor pairs.
Is 27 Prime or Composite? Why?
Composite. It has multiple factor pairs. 1 and 27 and 9 and 3.
True or false: 7 is a factor of 14.
TRUE: 7 x 2 = 14. So, 7 and 2 are both factors of 14.
True or False: 15 is a multiple of 3.
TRUE: 3, 6, 9, 12, 15
I have 50 cards and 3 players. Can I divide the cards evenly so there is none left over?
NO; 50 divided by 3 does not equal an even number.
List all the factors of 21.
1, 3, 7, 21
Is 29 Prime or Composite? Why?
Prime. Its only factor pair is 1 and 29.
True or false: 16 is a factor of 8.
FALSE: factors of 8 are 1, 2, 4, or 8.
What is one multiple of 9 besides 9.
9, 18, 27, 36, 45, 54...
I have 64 pencils. If I have 8 students, how many pencils will each student get if I divide the pencils up evenly?
8 pencils each.
What are TWO possible multiples of 9?
18, 27, 36, 45, 54, 63...
Give an example of a composite number. Why is it composite?
Did you choose a number that has MORE than 1 factor pair? 16, 21, 25, etc...
Name ALL of the factors for 20
1, 2, 4, 5, 10, 20
True or false: 80 is a multiple of 4.
True!: 4 x 20 = 80.
Can I divide up 39 cards among 3 friends evenly? If so, how many cards will each friend get?
Mike has 45 cookies and wants to give an even amount to each of his 5 friends. How many cookies will each friend get? Is it possible to divide the cookies evenly?
9 Cookies. Yes, it is possible.