Download study guide inv 2 and 3 - Colts Neck Township Schools

Prime Numbers: A number that only has 2 factors, the number 1 and itself.
Ex: 5 - 5 is a prime number because the only factors for 5 are 1 and 5.
Your turn: Name any 5 prime numbers.
Composite Numbers: A number that more than 2 factors.
Ex: 20 - 20 is a composite number because it has more than 2 factors.
The factors are: 1, 2, 4, 5, 10, 20
Your turn: Name any 5 composite numbers.
Factor: numbers that are multiplied to get a product.
Ex: 18 - all the factors of 18 are: 1, 2, 3, 6, 9, 18
Factors start with 1 and end with the number itself.
Your turn: Write all the factors for:
14 ___________________________________________
27 ___________________________________________
Product: The answer to numbers being multiplied
Ex: 6 x 2 = 12 12 is the product (it is also a multiple of both 6 and 2)
Your turn: what are the products for the following?
5 x 7 = _______
8 x 7 = _______
Multiple: the product of a whole number and another whole number.
Ex: Multiples of 2: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20 etc…
2 x 1 = 2 (2 is a multiple), 2 x 2 = 4 (4 is a multiple),
2 x 3 = 6 (6 is a multiple) …
Multiples are infinite, there is no end
Your turn: Write any three multiples for:
7 ___________________________________________
100 ___________________________________________
Greatest Common Factor (GCF)- The greatest factor that two or more
numbers share.
Ex: Factors of 16
1
16
2
Factors of 24
12
8
4
24
3
6
When looking in the intersection of Venn diagram, the highest common
factor is 8, therefore 8 is the GCF.
Your turn: Find the GCF of 12 and 36. You can do it with Venn diagrams, Tcharts, or
however you’d like.
GCF of 12 and 36 _______
When reading word problems that have key words/phrases such as:
greatest amount, greatest numbers, highest amount
this means you need to find the GCF of both numbers given.
Example:
Shelly wants to create party bags for her birthday. She has 24 candy bars and 12 ring pops. I
the party bags need to be the same without anything left over, what is the greatest number of
bags can she make?
24
12
1 24
1
12
2 12
2 6
3 8
3 4
4 6
Since 12 is the greatest common factor, she can make 12 bags.
Least Common Multiple LCM - The least multiple that 2 numbers
share.
Ex: multiples of 4
4
8
multiples of 5
5
16
20
10
15
12
40
25
30
35
When looking in the intersection of Venn diagram, the lowest common
multiple is 20 of 4 and 5 is 20, therefore, the LCM is 20.
Your turn: Find the LCM of 15 and 12. You can do it with Venn diagrams, lined, or
however you’d like.
When reading word problems that have key words/phrases such as:
Together again,
again,
at the same time,
both
this means you need to find the LCM of both numbers given.
Example:
Matthew goes hiking every 3 days and swimming every 5 days. He did both activities today. How
many days from now will he go both hiking and swimming again?
Multiples of 3: 3, 6, 9, 12, 15, 18, 21…
Multiples of 5: 5, 10, 15, 20…
Since 15 is the lowest common multiple, Matthew will swim and hike on the same day in 15 days.