factors, primes & composite numbers. learning objective: today factor numbers and determine if...
TRANSCRIPT
Factors, Primes & Composite Numbers
Learning Objective: Today factor numbers and determine if they are prime or composite.
What will we learn today?
Today we will factor numbers and determine if they are prime or composite.
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•What is 3 x 7?•What is the answer to a multiplication problem called?
Definition
• Product – An answer to a multiplication problem.
7 x 8 = 56Product
Definition
• Factor – a number that is multiplied by another to give a product.
7 x 8 = 56
Factors
What are the factors?(What two numbers make that product?)
6 x 7 = 427 x 9 = 638 x 6 = 484 x 9 = 36
6 & 77 & 98 & 64 & 9
Definition
• Prime Number – a number that has only two factors, itself and 1.
77 is prime because the only numbers
that will divide into it evenly are 1 and 7.
Examples of Prime Numbers
2, 3, 5, 7, 11, 13, 17, 19
Special Note:One is not a prime number.
Definition
• Composite number – a number that has more than two factors.
8The factors of 8 are 1, 2, 4, 8 because 1x8=8 and 2x4=8
Examples of Composite Numbers
4, 6, 8, 9, 10, 12, 14, 15
Special Note:Every whole number from 2 on is
either composite or prime.
Our Lonely 1
Special Note:One is not a prime nor a composite number.
It is not primebecause it doesnot have exactly
two differentfactors.
It is not composite
because it doesnot have morethan 2 factors.
Why is it important to understand?
How to use a factor tree
Step 1 – Write down two factors.(What two numbers make 48?)
48
48
6
848
How to use a factor treeStep 2 – Find factors of these numbers until
all factors are prime.(what makes a 6? What makes an 8?)
48
6
2
3
8
2
4
48
48
6
8
48
6
2
3
8
How to use a factor treeStep 2 – Find factors of these numbers
until all factors are prime numbers.48
6
2
3
8
2
4
2
2
48
6
2
3
8
2
4
How to use a Factor TreeStep 3 – Write the numbers from leastto greatest.Determine if the number is prime or composite.
48
6
2
3
8
2
4
2
2
Factors of 48 are:1,2,3,4,6,8,48Hint: only write each digit once.Composite
Factor this number
6 Factors of 6 are:
Hint: only write each digit once.
Composite6
2
3 1,2,4,6
Step 1 – Write down two factors.Step 2 – Find factors of these numbers until all factors are prime
Step 3 – Write the numbers from least to greatest. Determine if the number is prime or composite.
Factor this number8
2
4
2
2
Factors of 8 are:
Hint: only write each digit once.
Composite8
2
48
1,2,4,8
Step 1 – Write down two factors.Step 2 – Find factors of these numbers until all factors are prime
Step 3 – Write the numbers from least to greatest. Determine if the number is prime or composite.
Factor this number
10 Factors of 6 are:
Hint: only write each digit once.
Composite10
2
5 1,2,5,10
Factor this number
20
2
5
2
2
Factors of 8 are:
Hint: only write each digit once.
Composite20
5
420
1,2,4,5,20
Factor this number
7 Factors of 7 are:1,7Hint: only write each digit once.
Prime
Factor this number
13 Factors of 13 are:1,13Hint: only write each digit once.
Prime
Now you try!Factor this number
25Factors of ___ are:_____________
Hint: only write each digit once. Don’t forget 1 and itself!
Prime or composite?
What did we learn to factor today?Why is it important?
Now you try!Factor this number
24Factors of ___ are:_____________
Hint: only write each digit once. Don’t forget 1 and itself!
Prime or composite?
Now you try!Factor this number
17
Prime or composite?
Factors of ___ are:_____________
Hint: only write each digit once. Don’t forget 1 and itself!
Factor this numberFactors of __________ are:
Hint: only write each digit once. Don’t forget 1 and itself!
Prime or composite?
Print this slide for use in whiteboards
Step 1 – Write down two factors.Step 2 – Find factors of these numbers until all factors are prime
Step 3 – Write the numbers from least to greatest. Determine if the number is prime or composite.