Transcript Prime Time 1.6

Prime Time 1.6
Objective:
Write prime factorization using
exponents
Is it divisible by Only if…
2
The ones digit is divisible by 2
3
5
The sum of the digits is divisible
by 3
The last two digits of the # are
divisible by 4
It ends in 0 or 5
6
The # is divisible by 2 and 3
9
The sum of the digits is divisible
by 9
The # ends in 0
4
10
Did you know?
• Did you know that prime means “first or
original”?
• Did you know that composite means
“made up of different parts”?
• Did you know that factor means “one
thing that influences or contributes to
another”?
• How do these everyday meanings related
to their math meanings?
Tell whether each number is
prime, composite, or neither
•
•
•
•
1) 28
2) 11
3) 1
4) 2
Prime Factorization
• Prime Factorization: a composite number
expressed as a product of prime numbers.
• Factor Trees are often used to help you
organize your prime factorization.
Example
• Find the prime factorizations of the
numbers:
54
72
• List the numbers in order from least to
greatest
• Can you write the answers in exponent
form?
Powers and Exponents
• A product of identical factors can be
written using an exponent and a base.
Exponent
• 32 = 2 x 2 x 2 x 2 x 2 = 2^5
Base
Numbers expressed using
exponents are called powers.
Powers
Words
2^5
2 to the fifth power
3^2
3 to the second power or
3 squared
10 to the third power or
10 cubed
7 to the forth power
10 ^ 3
7^4
What about when the exponent is 0
or 1?
• If no exponent is
given the exponent is
considered to be 1.
• This does not change
the value.
• For example:
• 5^1=5
• If the exponent is
given is 0, the value is
one.
• (This is 7th grade
math)
• For example:
• 5^0=1
Practice
• Write using exponents:
• 5x5x5x5=
• 6x6x6=
• 12 x 12 x 12 x 12 =
Practice
• Find the prime factorization of the
following numbers. Write the final answer
using exponents.
8
64
256
Calculator
• You can use a calculator to evaluate
powers.
• To find 3 to the forth power press
3 ^ 4
What is the answer?