2.4 prime numbers and factors w

74
Prime Numbers http://www.lahc.edu/math/frankma.htm

description

 

Transcript of 2.4 prime numbers and factors w

Page 1: 2.4 prime numbers and factors w

Prime Numbers

http://www.lahc.edu/math/frankma.htm

Page 2: 2.4 prime numbers and factors w

Prime NumbersIt we are to divide 6 pieces of candy into bag(s) so each bag has the same amount, we may do it in the following manner.

If we have 3 candies, we may bag them in the obvious manner

or

or

or

Besides dividing them in the “obvious” ways: put all 6 candies into one bag, or put one candy into 6 separate bags,

we may also divide the6 pieces into smaller bags as:

but we can’t bag them into other smaller bags evenly.

Because 3 can’t be divided into smaller groups, except as singles, we say that “3 is prime.”

On the other hand 6 = 2 x 3, i.e. 6 can be broken up into smaller groups, therefore 6 is not prime.

2 x 3 3 x 2

Page 3: 2.4 prime numbers and factors w

Let’s define these important relations precisely. Prime Numbers

Page 4: 2.4 prime numbers and factors w

Let’s define these important relations precisely. If A, B and C are non-zero numbers such that A x B = C, then we say that “A (or B) is a factor of C”, or that “C is a multiple of A (or B)”.

Prime Numbers

Page 5: 2.4 prime numbers and factors w

Let’s define these important relations precisely. If A, B and C are non-zero numbers such that A x B = C, then we say that “A (or B) is a factor of C”, or that “C is a multiple of A (or B)”.

Prime Numbers

In other words, A is factor of C, or that C is a multiple of A, if C may be divided by A evenly.

Page 6: 2.4 prime numbers and factors w

Let’s define these important relations precisely. If A, B and C are non-zero numbers such that A x B = C, then we say that “A (or B) is a factor of C”, or that “C is a multiple of A (or B)”.

For example, 6 may be dividedly 1, 2, 3 and 6 evenly, hence 1, 2, 3, and 6 are factors of 6, or 6 is a multiple of 1, 2, 3 and 6.

Prime Numbers

In other words, A is factor of C, or that C is a multiple of A, if C may be divided by A evenly.

Page 7: 2.4 prime numbers and factors w

Let’s define these important relations precisely. If A, B and C are non-zero numbers such that A x B = C, then we say that “A (or B) is a factor of C”, or that “C is a multiple of A (or B)”.

For example, 6 may be dividedly 1, 2, 3 and 6 evenly, hence 1, 2, 3, and 6 are factors of 6, or 6 is a multiple of 1, 2, 3 and 6. Note that the multiples of 6 are 6(= 1x6) , 12(= 2x6) , 18(= 3x6) etc.

Prime Numbers

In other words, A is factor of C, or that C is a multiple of A, if C may be divided by A evenly.

Page 8: 2.4 prime numbers and factors w

Let’s define these important relations precisely. If A, B and C are non-zero numbers such that A x B = C, then we say that “A (or B) is a factor of C”, or that “C is a multiple of A (or B)”.

For example, 6 may be dividedly 1, 2, 3 and 6 evenly, hence 1, 2, 3, and 6 are factors of 6, or 6 is a multiple of 1, 2, 3 and 6. Note that the multiples of 6 are 6(= 1x6) , 12(= 2x6) , 18(= 3x6) etc.

Prime Numbers

In other words, A is factor of C, or that C is a multiple of A, if C may be divided by A evenly.

Example A. a. 12 pieces of candy are to be put into one or more bags evenly. How many piece(s) of candy in each bag are possible?(These numbers are the factors of 12.)

Page 9: 2.4 prime numbers and factors w

Let’s define these important relations precisely. If A, B and C are non-zero numbers such that A x B = C, then we say that “A (or B) is a factor of C”, or that “C is a multiple of A (or B)”.

For example, 6 may be dividedly 1, 2, 3 and 6 evenly, hence 1, 2, 3, and 6 are factors of 6, or 6 is a multiple of 1, 2, 3 and 6. Note that the multiples of 6 are 6(= 1x6) , 12(= 2x6) , 18(= 3x6) etc..

Prime Numbers

In other words, A is factor of C, or that C is a multiple of A, if C may be divided by A evenly.

Example A. a. 12 pieces of candy are to be put into one or more bags evenly. How many piece(s) of candy in each bag are possible?(These numbers are the factors of 12.)

We may have 1 piece/per bag,

Page 10: 2.4 prime numbers and factors w

Let’s define these important relations precisely. If A, B and C are non-zero numbers such that A x B = C, then we say that “A (or B) is a factor of C”, or that “C is a multiple of A (or B)”.

For example, 6 may be dividedly 1, 2, 3 and 6 evenly, hence 1, 2, 3, and 6 are factors of 6, or 6 is a multiple of 1, 2, 3 and 6. Note that the multiples of 6 are 6(= 1x6) , 12(= 2x6) , 18(= 3x6) etc.

Prime Numbers

In other words, A is factor of C, or that C is a multiple of A, if C may be divided by A evenly.

Example A. a. 12 pieces of candy are to be put into one or more bags evenly. How many piece(s) of candy in each bag are possible?(These numbers are the factors of 12.)

We may have 1 piece/per bag, 2 pieces/bag,

Page 11: 2.4 prime numbers and factors w

Let’s define these important relations precisely. If A, B and C are non-zero numbers such that A x B = C, then we say that “A (or B) is a factor of C”, or that “C is a multiple of A (or B)”.

For example, 6 may be dividedly 1, 2, 3 and 6 evenly, hence 1, 2, 3, and 6 are factors of 6, or 6 is a multiple of 1, 2, 3 and 6. Note that the multiples of 6 are 6(= 1x6) , 12(= 2x6) , 18(= 3x6) etc.

Prime Numbers

In other words, A is factor of C, or that C is a multiple of A, if C may be divided by A evenly.

Example A. a. 12 pieces of candy are to be put into one or more bags evenly. How many piece(s) of candy in each bag are possible?(These numbers are the factors of 12.)

We may have 1 piece/per bag, 2 pieces/bag, 3 pieces/ bag,

Page 12: 2.4 prime numbers and factors w

Let’s define these important relations precisely. If A, B and C are non-zero numbers such that A x B = C, then we say that “A (or B) is a factor of C”, or that “C is a multiple of A (or B)”.

For example, 6 may be dividedly 1, 2, 3 and 6 evenly, hence 1, 2, 3, and 6 are factors of 6, or 6 is a multiple of 1, 2, 3 and 6. Note that the multiples of 6 are 6(= 1x6) , 12(= 2x6) , 18(= 3x6) etc.

Prime Numbers

In other words, A is factor of C, or that C is a multiple of A, if C may be divided by A evenly.

Example A. a. 12 pieces of candy are to be put into one or more bags evenly. How many piece(s) of candy in each bag are possible?(These numbers are the factors of 12.)

We may have 1 piece/per bag, 2 pieces/bag, 3 pieces/ bag, 4 pieces/bag, 6 pieces/bag, or 12 pieces/bag.

Page 13: 2.4 prime numbers and factors w

Let’s define these important relations precisely. If A, B and C are non-zero numbers such that A x B = C, then we say that “A (or B) is a factor of C”, or that “C is a multiple of A (or B)”.

For example, 6 may be dividedly 1, 2, 3 and 6 evenly, hence 1, 2, 3, and 6 are factors of 6, or 6 is a multiple of 1, 2, 3 and 6. Note that the multiples of 6 are 6(= 1x6) , 12(= 2x6) , 18(= 3x6) etc.

Prime Numbers

In other words, A is factor of C, or that C is a multiple of A, if C may be divided by A evenly.

Example A. a. 12 pieces of candy are to be put into one or more bags evenly. How many piece(s) of candy in each bag are possible?(These numbers are the factors of 12.)

We may have 1 piece/per bag, 2 pieces/bag, 3 pieces/ bag, 4 pieces/bag, 6 pieces/bag, or 12 pieces/bag. So the factors of 12 are 1, 2, 3, 4, 6, and 12.

Page 14: 2.4 prime numbers and factors w

Prime Numbersb. A box contains bag(s) of candy and each bag has 12 pieces, how many candies in the box are possible? (These numbers are the multiples of 12.)

Page 15: 2.4 prime numbers and factors w

Prime Numbersb. A box contains bag(s) of candy and each bag has 12 pieces, how many candies in the box are possible? (These numbers are the multiples of 12.) There might be 1 bag or 2 bags or 3 bags, etc.. each with 12 pieces.

Page 16: 2.4 prime numbers and factors w

Prime Numbersb. A box contains bag(s) of candy and each bag has 12 pieces, how many candies in the box are possible? (These numbers are the multiples of 12.) There might be 1 bag or 2 bags or 3 bags, etc.. each with 12 pieces. So the box may have 12 =1x12, 24 =2x12, 36 =3x12, 48 =4x12, 60, ..., pieces, or that the multiples of 12 are 12, 24, 36, 48, …

Page 17: 2.4 prime numbers and factors w

A number C is a prime number if C only has 1 and itself as factors, i.e. C can be divided evenly only by 1 and itself.

Prime Numbersb. A box contains bag(s) of candy and each bag has 12 pieces, how many candies in the box are possible? (These numbers are the multiples of 12.) There might be 1 bag or 2 bags or 3 bags, etc.. each with 12 pieces. So the box may have 12 =1x12, 24 =2x12, 36 =3x12, 48 =4x12, 60, ..., pieces, or that the multiples of 12 are 12, 24, 36, 48, …

Page 18: 2.4 prime numbers and factors w

A number C is a prime number if C only has 1 and itself as factors, i.e. C can be divided evenly only by 1 and itself.The following are the first few prime numbers: 2, 3, 5, 7, 11,13,..;

Prime Numbersb. A box contains bag(s) of candy and each bag has 12 pieces, how many candies in the box are possible? (These numbers are the multiples of 12.) There might be 1 bag or 2 bags or 3 bags, etc.. each with 12 pieces. So the box may have 12 =1x12, 24 =2x12, 36 =3x12, 48 =4x12, 60, ..., pieces, or that the multiples of 12 are 12, 24, 36, 48, …

Page 19: 2.4 prime numbers and factors w

A number C is a prime number if C only has 1 and itself as factors, i.e. C can be divided evenly only by 1 and itself.The following are the first few prime numbers: 2, 3, 5, 7, 11,13,..;

Prime Numbers

but 4 = 2 x 2, 6 = 2 x 3, 8 = 2 x 2 x 2, 9 = 3 x 3, are not prime.

b. A box contains bag(s) of candy and each bag has 12 pieces, how many candies in the box are possible? (These numbers are the multiples of 12.) There might be 1 bag or 2 bags or 3 bags, etc.. each with 12 pieces. So the box may have 12 =1x12, 24 =2x12, 36 =3x12, 48 =4x12, 60, ..., pieces, or that the multiples of 12 are 12, 24, 36, 48, …

Page 20: 2.4 prime numbers and factors w

A number C is a prime number if C only has 1 and itself as factors, i.e. C can be divided evenly only by 1 and itself.The following are the first few prime numbers: 2, 3, 5, 7, 11,13,..;

Prime Numbers

but 4 = 2 x 2, 6 = 2 x 3, 8 = 2 x 2 x 2, 9 = 3 x 3, are not prime.

b. A box contains bag(s) of candy and each bag has 12 pieces, how many candies in the box are possible? (These numbers are the multiples of 12.) There might be 1 bag or 2 bags or 3 bags, etc.. each with 12 pieces. So the box may have 12 =1x12, 24 =2x12, 36 =3x12, 48 =4x12, 60, ..., pieces, or that the multiples of 12 are 12, 24, 36, 48, …

The problem of determining easily which numbers are prime and which are not, is a major problem in mathematics.

Page 21: 2.4 prime numbers and factors w

A number C is a prime number if C only has 1 and itself as factors, i.e. C can be divided evenly only by 1 and itself.The following are the first few prime numbers: 2, 3, 5, 7, 11,13,..;

Prime Numbers

but 4 = 2 x 2, 6 = 2 x 3, 8 = 2 x 2 x 2, 9 = 3 x 3, are not prime.

b. A box contains bag(s) of candy and each bag has 12 pieces, how many candies in the box are possible? (These numbers are the multiples of 12.) There might be 1 bag or 2 bags or 3 bags, etc.. each with 12 pieces. So the box may have 12 =1x12, 24 =2x12, 36 =3x12, 48 =4x12, 60, ..., pieces, or that the multiples of 12 are 12, 24, 36, 48, …

http://en.wikipedia.org/wiki/Sieve_of_Eratosthenes

The link below has a good animation of one method of trying to determine which numbers are prime and which are not.

The problem of determining easily which numbers are prime and which are not, is a major problem in mathematics.

Page 22: 2.4 prime numbers and factors w

Exponents and Prime FactoringBelow we will write “A x B” as “A*B” for shorter notation.

Page 23: 2.4 prime numbers and factors w

Exponents and Prime Factoring

Recall that to simplify the notation for repetitive multiplication, we write 2*2 as 22, 2*2*2 as 23, 2*2*2*2 as 24 and so on.

Below we will write “A x B” as “A*B” for shorter notation.

Page 24: 2.4 prime numbers and factors w

Exponents and Prime Factoring

Recall that to simplify the notation for repetitive multiplication, we write 2*2 as 22, 2*2*2 as 23, 2*2*2*2 as 24 and so on. We write x*x*x…*x as xN where N is the number of times that x is multiplied to itself.

Below we will write “A x B” as “A*B” for shorter notation.

Page 25: 2.4 prime numbers and factors w

Exponents and Prime Factoring

Recall that to simplify the notation for repetitive multiplication, we write 2*2 as 22, 2*2*2 as 23, 2*2*2*2 as 24 and so on. We write x*x*x…*x as xN where N is the number of times that x is multiplied to itself.

Below we will write “A x B” as “A*B” for shorter notation.

N is called the exponent, or the power and x is called the base.

Page 26: 2.4 prime numbers and factors w

Exponents and Prime Factoring

Recall that to simplify the notation for repetitive multiplication, we write 2*2 as 22, 2*2*2 as 23, 2*2*2*2 as 24 and so on.

Example B. Calculate. 32 43

We write x*x*x…*x as xN where N is the number of times that x is multiplied to itself.

Below we will write “A x B” as “A*B” for shorter notation.

==

N is called the exponent, or the power and x is called the base.

Page 27: 2.4 prime numbers and factors w

Exponents and Prime Factoring

Recall that to simplify the notation for repetitive multiplication, we write 2*2 as 22, 2*2*2 as 23, 2*2*2*2 as 24 and so on.

Example B. Calculate. 32 43

We write x*x*x…*x as xN where N is the number of times that x is multiplied to itself.

Below we will write “A x B” as “A*B” for shorter notation.

= 3*3 = 9 =

N is called the exponent, or the power and x is called the base.

Page 28: 2.4 prime numbers and factors w

Exponents and Prime Factoring

Recall that to simplify the notation for repetitive multiplication, we write 2*2 as 22, 2*2*2 as 23, 2*2*2*2 as 24 and so on.

Example B. Calculate. 32 43

We write x*x*x…*x as xN where N is the number of times that x is multiplied to itself.

Below we will write “A x B” as “A*B” for shorter notation.

= 3*3 = 9 =

(note that 32 is not 3*2 = 6)

N is called the exponent, or the power and x is called the base.

Page 29: 2.4 prime numbers and factors w

Exponents and Prime Factoring

Recall that to simplify the notation for repetitive multiplication, we write 2*2 as 22, 2*2*2 as 23, 2*2*2*2 as 24 and so on.

Example B. Calculate. 32 43

We write x*x*x…*x as xN where N is the number of times that x is multiplied to itself.

Below we will write “A x B” as “A*B” for shorter notation.

= 3*3 = 9 = 4*4*4 = 64

(note that 32 is not 3*2 = 6)

N is called the exponent, or the power and x is called the base.

Page 30: 2.4 prime numbers and factors w

Exponents and Prime Factoring

Recall that to simplify the notation for repetitive multiplication, we write 2*2 as 22, 2*2*2 as 23, 2*2*2*2 as 24 and so on.

Example B. Calculate. 32 43

We write x*x*x…*x as xN where N is the number of times that x is multiplied to itself.

Below we will write “A x B” as “A*B” for shorter notation.

= 3*3 = 9 = 4*4*4 = 64

(note that 32 is not 3*2 = 6)(note that 43 is not 4*3 = 12)

N is called the exponent, or the power and x is called the base.

Page 31: 2.4 prime numbers and factors w

The phrase to factor a number C means to write C as a product, i.e. to write C as # * # *** # where # might be any number.

Exponents and Prime Factoring

Recall that to simplify the notation for repetitive multiplication, we write 2*2 as 22, 2*2*2 as 23, 2*2*2*2 as 24 and so on.

Example B. Calculate. 32 43

We write x*x*x…*x as xN where N is the number of times that x is multiplied to itself.

Below we will write “A x B” as “A*B” for shorter notation.

= 3*3 = 9 = 4*4*4 = 64

(note that 32 is not 3*2 = 6)(note that 43 is not 4*3 = 12)

N is called the exponent, or the power and x is called the base.

Page 32: 2.4 prime numbers and factors w

The phrase to factor a number C means to write C as a product, i.e. to write C as # * # *** # where # might be any number.

Exponents and Prime Factoring

Recall that to simplify the notation for repetitive multiplication, we write 2*2 as 22, 2*2*2 as 23, 2*2*2*2 as 24 and so on.

Example B. Calculate. 32 43

We write x*x*x…*x as xN where N is the number of times that x is multiplied to itself.

For example 12 can be factored as 12 = 2*6 = 3*4 = 2*2*3.

Below we will write “A x B” as “A*B” for shorter notation.

= 3*3 = 9 = 4*4*4 = 64

(note that 32 is not 3*2 = 6)(note that 43 is not 4*3 = 12)

N is called the exponent, or the power and x is called the base.

Page 33: 2.4 prime numbers and factors w

The phrase to factor a number C means to write C as a product, i.e. to write C as # * # *** # where # might be any number.

A factorization is complete if all the factors that appear in the multiplication are prime numbers.

Exponents and Prime Factoring

Recall that to simplify the notation for repetitive multiplication, we write 2*2 as 22, 2*2*2 as 23, 2*2*2*2 as 24 and so on.

Example B. Calculate. 32 43

We write x*x*x…*x as xN where N is the number of times that x is multiplied to itself.

For example 12 can be factored as 12 = 2*6 = 3*4 = 2*2*3.

Below we will write “A x B” as “A*B” for shorter notation.

= 3*3 = 9 = 4*4*4 = 64

(note that 32 is not 3*2 = 6)(note that 43 is not 4*3 = 12)

N is called the exponent, or the power and x is called the base.

Page 34: 2.4 prime numbers and factors w

The phrase to factor a number C means to write C as a product, i.e. to write C as # * # *** # where # might be any number.

A factorization is complete if all the factors that appear in the multiplication are prime numbers.

Exponents and Prime Factoring

Recall that to simplify the notation for repetitive multiplication, we write 2*2 as 22, 2*2*2 as 23, 2*2*2*2 as 24 and so on.

Example B. Calculate. 32 43

We write x*x*x…*x as xN where N is the number of times that x is multiplied to itself.

For example 12 can be factored as 12 = 2*6 = 3*4 = 2*2*3.

Below we will write “A x B” as “A*B” for shorter notation.

= 3*3 = 9 = 4*4*4 = 64

(note that 32 is not 3*2 = 6)(note that 43 is not 4*3 = 12)

So 12 = 2*2*3 is factored completely because 2 and 3 are prime,

N is called the exponent, or the power and x is called the base.

Page 35: 2.4 prime numbers and factors w

The phrase to factor a number C means to write C as a product, i.e. to write C as # * # *** # where # might be any number.

A factorization is complete if all the factors that appear in the multiplication are prime numbers.

Exponents and Prime Factoring

Recall that to simplify the notation for repetitive multiplication, we write 2*2 as 22, 2*2*2 as 23, 2*2*2*2 as 24 and so on.

Example B. Calculate. 32 43

We write x*x*x…*x as xN where N is the number of times that x is multiplied to itself.

For example 12 can be factored as 12 = 2*6 = 3*4 = 2*2*3.

Below we will write “A x B” as “A*B” for shorter notation.

= 3*3 = 9 = 4*4*4 = 64

(note that 32 is not 3*2 = 6)(note that 43 is not 4*3 = 12)

So 12 = 2*2*3 is factored completely because 2 and 3 are prime, but 12 = 2* 6 is not factored completely because 6 is not a prime.

N is called the exponent, or the power and x is called the base.

Page 36: 2.4 prime numbers and factors w

Numbers that are factored completely may be written using the exponential notation.

Exponents

Page 37: 2.4 prime numbers and factors w

Numbers that are factored completely may be written using the exponential notation.Hence, factored completely, 12 = 2*2*3 = 22

*3,

Exponents

Page 38: 2.4 prime numbers and factors w

Numbers that are factored completely may be written using the exponential notation.Hence, factored completely, 12 = 2*2*3 = 22

*3,200 = 8*25 = 2*2*2*5*5

Exponents

Page 39: 2.4 prime numbers and factors w

Numbers that are factored completely may be written using the exponential notation.Hence, factored completely, 12 = 2*2*3 = 22

*3,200 = 8*25 = 2*2*2*5*5 = 23

* 52.

Exponents

Page 40: 2.4 prime numbers and factors w

Numbers that are factored completely may be written using the exponential notation.Hence, factored completely, 12 = 2*2*3 = 22

*3,200 = 8*25 = 2*2*2*5*5 = 23

* 52.Each number has a unique form when its completely factored into prime factors and arranged in order.

Exponents

Page 41: 2.4 prime numbers and factors w

Numbers that are factored completely may be written using the exponential notation.Hence, factored completely, 12 = 2*2*3 = 22

*3,200 = 8*25 = 2*2*2*5*5 = 23

* 52.Each number has a unique form when its completely factored into prime factors and arranged in order. This is analogous to chemistry where each chemical has a unique chemical composition of basic elements such as H20 for water.

Exponents

Page 42: 2.4 prime numbers and factors w

Numbers that are factored completely may be written using the exponential notation.Hence, factored completely, 12 = 2*2*3 = 22

*3,200 = 8*25 = 2*2*2*5*5 = 23

* 52.Each number has a unique form when its completely factored into prime factors and arranged in order. This is analogous to chemistry where each chemical has a unique chemical composition of basic elements such as H20 for water.

Larger numbers may be factored using a vertical format.

Exponents

Page 43: 2.4 prime numbers and factors w

Numbers that are factored completely may be written using the exponential notation.Hence, factored completely, 12 = 2*2*3 = 22

*3,200 = 8*25 = 2*2*2*5*5 = 23

* 52.Each number has a unique form when its completely factored into prime factors and arranged in order. This is analogous to chemistry where each chemical has a unique chemical composition of basic elements such as H20 for water.

Larger numbers may be factored using a vertical format. Example C. Factor 144 completely. (Vertical format)

Exponents

Page 44: 2.4 prime numbers and factors w

Numbers that are factored completely may be written using the exponential notation.Hence, factored completely, 12 = 2*2*3 = 22

*3,200 = 8*25 = 2*2*2*5*5 = 23

* 52.Each number has a unique form when its completely factored into prime factors and arranged in order. This is analogous to chemistry where each chemical has a unique chemical composition of basic elements such as H20 for water.

Larger numbers may be factored using a vertical format. Example C. Factor 144 completely. (Vertical format)

144

12 12

Exponents

Page 45: 2.4 prime numbers and factors w

Numbers that are factored completely may be written using the exponential notation.Hence, factored completely, 12 = 2*2*3 = 22

*3,200 = 8*25 = 2*2*2*5*5 = 23

* 52.Each number has a unique form when its completely factored into prime factors and arranged in order. This is analogous to chemistry where each chemical has a unique chemical composition of basic elements such as H20 for water.

Larger numbers may be factored using a vertical format. Example C. Factor 144 completely. (Vertical format)

144

12 12

3 4 3 4

Exponents

Page 46: 2.4 prime numbers and factors w

Numbers that are factored completely may be written using the exponential notation.Hence, factored completely, 12 = 2*2*3 = 22

*3,200 = 8*25 = 2*2*2*5*5 = 23

* 52.Each number has a unique form when its completely factored into prime factors and arranged in order. This is analogous to chemistry where each chemical has a unique chemical composition of basic elements such as H20 for water.

Larger numbers may be factored using a vertical format. Example C. Factor 144 completely. (Vertical format)

144

12 12

3 4 3 4

2 22 2

Exponents

Page 47: 2.4 prime numbers and factors w

Numbers that are factored completely may be written using the exponential notation.Hence, factored completely, 12 = 2*2*3 = 22

*3,200 = 8*25 = 2*2*2*5*5 = 23

* 52.Each number has a unique form when its completely factored into prime factors and arranged in order. This is analogous to chemistry where each chemical has a unique chemical composition of basic elements such as H20 for water.

Larger numbers may be factored using a vertical format. Example C. Factor 144 completely. (Vertical format)

144

12 12

3 4 3 4

2 22 2

Gather all the prime numbers at the end of the branches we have 144 = 3*3*2*2*2*2 = 32 * 24.

Exponents

Page 48: 2.4 prime numbers and factors w

Numbers that are factored completely may be written using the exponential notation.Hence, factored completely, 12 = 2*2*3 = 22

*3,200 = 8*25 = 2*2*2*5*5 = 23

* 52.Each number has a unique form when its completely factored into prime factors and arranged in order. This is analogous to chemistry where each chemical has a unique chemical composition of basic elements such as H20 for water.

Larger numbers may be factored using a vertical format. Example C. Factor 144 completely. (Vertical format)

144

12 12

3 4 3 4

2 22 2

Gather all the prime numbers at the end of the branches we have 144 = 3*3*2*2*2*2 = 32 * 24.Note that we obtain the same answer regardless how we factor at each step.

Exponents

Page 49: 2.4 prime numbers and factors w

Basic LawsWe summarize the basic laws of + and * operations again.

Page 50: 2.4 prime numbers and factors w

Basic Laws

The Associative Law for Addition and Multiplication

The Commutative Law for Addition and Multiplication

We summarize the basic laws of + and * operations again.

Page 51: 2.4 prime numbers and factors w

Basic Laws

The Associative Law for Addition and Multiplication

The Commutative Law for Addition and Multiplicationa + b = b + a a * b = b * a

We summarize the basic laws of + and * operations again.

Page 52: 2.4 prime numbers and factors w

Basic Laws

The Associative Law for Addition and Multiplication

The Commutative Law for Addition and Multiplicationa + b = b + a a * b = b * a For example, 3 + 4 = 4 + 3 = 7 and 4*3 = 3*4 = 12.

We summarize the basic laws of + and * operations again.

Page 53: 2.4 prime numbers and factors w

( a + b ) + c = a + ( b + c ) ( a * b ) * c = a * ( b * c )

Basic Laws

The Associative Law for Addition and Multiplication

The Commutative Law for Addition and Multiplicationa + b = b + a a * b = b * a For example, 3 + 4 = 4 + 3 = 7 and 4*3 = 3*4 = 12.

We summarize the basic laws of + and * operations again.

Page 54: 2.4 prime numbers and factors w

( a + b ) + c = a + ( b + c ) ( a * b ) * c = a * ( b * c )

Basic Laws

For example, (1 + 2) + 3 = 3 + 3 = 6, is the same as 1 + (2 + 3) = 1 + 5 = 6.

The Associative Law for Addition and Multiplication

The Commutative Law for Addition and Multiplicationa + b = b + a a * b = b * a For example, 3 + 4 = 4 + 3 = 7 and 4*3 = 3*4 = 12.

We summarize the basic laws of + and * operations again.

Page 55: 2.4 prime numbers and factors w

( a + b ) + c = a + ( b + c ) ( a * b ) * c = a * ( b * c )

Basic Laws

For example, (1 + 2) + 3 = 3 + 3 = 6, is the same as 1 + (2 + 3) = 1 + 5 = 6.

The Associative Law for Addition and Multiplication

The Commutative Law for Addition and Multiplicationa + b = b + a a * b = b * a For example, 3 + 4 = 4 + 3 = 7 and 4*3 = 3*4 = 12.

We summarize the basic laws of + and * operations again.

These laws allow us to + or * numbers in any order we wish.

Page 56: 2.4 prime numbers and factors w

( a + b ) + c = a + ( b + c ) ( a * b ) * c = a * ( b * c )

Basic Laws

For example, (1 + 2) + 3 = 3 + 3 = 6, is the same as 1 + (2 + 3) = 1 + 5 = 6.

The Associative Law for Addition and Multiplication

The Commutative Law for Addition and Multiplicationa + b = b + a a * b = b * a For example, 3 + 4 = 4 + 3 = 7 and 4*3 = 3*4 = 12.

We summarize the basic laws of + and * operations again.

These laws allow us to + or * numbers in any order we wish.

Example D. Calculate.

14 + 3 + 16 + 8 + 35 + 15

Page 57: 2.4 prime numbers and factors w

( a + b ) + c = a + ( b + c ) ( a * b ) * c = a * ( b * c )

Basic Laws

For example, (1 + 2) + 3 = 3 + 3 = 6, is the same as 1 + (2 + 3) = 1 + 5 = 6.

The Associative Law for Addition and Multiplication

The Commutative Law for Addition and Multiplicationa + b = b + a a * b = b * a For example, 3 + 4 = 4 + 3 = 7 and 4*3 = 3*4 = 12.

We summarize the basic laws of + and * operations again.

These laws allow us to + or * numbers in any order we wish.

Example D. Calculate.

14 + 3 + 16 + 8 + 35 + 15 = 30

Page 58: 2.4 prime numbers and factors w

( a + b ) + c = a + ( b + c ) ( a * b ) * c = a * ( b * c )

Basic Laws

For example, (1 + 2) + 3 = 3 + 3 = 6, is the same as 1 + (2 + 3) = 1 + 5 = 6.

The Associative Law for Addition and Multiplication

The Commutative Law for Addition and Multiplicationa + b = b + a a * b = b * a For example, 3 + 4 = 4 + 3 = 7 and 4*3 = 3*4 = 12.

We summarize the basic laws of + and * operations again.

These laws allow us to + or * numbers in any order we wish.

Example D. Calculate.

14 + 3 + 16 + 8 + 35 + 15 = 30 + 50

Page 59: 2.4 prime numbers and factors w

( a + b ) + c = a + ( b + c ) ( a * b ) * c = a * ( b * c )

Basic Laws

For example, (1 + 2) + 3 = 3 + 3 = 6, is the same as 1 + (2 + 3) = 1 + 5 = 6.

The Associative Law for Addition and Multiplication

The Commutative Law for Addition and Multiplicationa + b = b + a a * b = b * a For example, 3 + 4 = 4 + 3 = 7 and 4*3 = 3*4 = 12.

We summarize the basic laws of + and * operations again.

These laws allow us to + or * numbers in any order we wish.

Example D. Calculate.

14 + 3 + 16 + 8 + 35 + 15 = 30 + 50+ 11

Page 60: 2.4 prime numbers and factors w

( a + b ) + c = a + ( b + c ) ( a * b ) * c = a * ( b * c )

Basic Laws

For example, (1 + 2) + 3 = 3 + 3 = 6, is the same as 1 + (2 + 3) = 1 + 5 = 6.

The Associative Law for Addition and Multiplication

The Commutative Law for Addition and Multiplicationa + b = b + a a * b = b * a For example, 3 + 4 = 4 + 3 = 7 and 4*3 = 3*4 = 12.

We summarize the basic laws of + and * operations again.

These laws allow us to + or * numbers in any order we wish.

Example D. Calculate.

14 + 3 + 16 + 8 + 35 + 15 = 91 = 30 + 50+ 11

Page 61: 2.4 prime numbers and factors w

Basic LawsHowever, subtraction and division are not commutative nor associative.

Page 62: 2.4 prime numbers and factors w

Basic Laws

For example, 2 1 1 2,

However, subtraction and division are not commutative nor associative.

Page 63: 2.4 prime numbers and factors w

Basic Laws

For example, 2 1 1 2, and that ( 3 – 2 ) – 1 = 0 is different from 3 – ( 2 – 1 ) = 2.

However, subtraction and division are not commutative nor associative.

Page 64: 2.4 prime numbers and factors w

Basic Laws

For example, 2 1 1 2, and that ( 3 – 2 ) – 1 = 0 is different from 3 – ( 2 – 1 ) = 2. Thus when subtracting or dividing, we have to determine who is in the front and who is in the back.

However, subtraction and division are not commutative nor associative.

Page 65: 2.4 prime numbers and factors w

Basic Laws

For example, 2 1 1 2, and that ( 3 – 2 ) – 1 = 0 is different from 3 – ( 2 – 1 ) = 2. Thus when subtracting or dividing, we have to determine who is in the front and who is in the back.

However, subtraction and division are not commutative nor associative.

Distributive Law: a*(b ± c) = a*b ± a*c

.

Page 66: 2.4 prime numbers and factors w

Basic Laws

For example, 2 1 1 2, and that ( 3 – 2 ) – 1 = 0 is different from 3 – ( 2 – 1 ) = 2. Thus when subtracting or dividing, we have to determine who is in the front and who is in the back.

However, subtraction and division are not commutative nor associative.

Distributive Law: a*(b ± c) = a*b ± a*c

. Example E. Do 5*( 3 + 4 ) two different ways and show the results are the same.

Page 67: 2.4 prime numbers and factors w

Basic Laws

For example, 2 1 1 2, and that ( 3 – 2 ) – 1 = 0 is different from 3 – ( 2 – 1 ) = 2. Thus when subtracting or dividing, we have to determine who is in the front and who is in the back.

However, subtraction and division are not commutative nor associative.

Distributive Law: a*(b ± c) = a*b ± a*c

. Example E. Do 5*( 3 + 4 ) two different ways and show the results are the same.

Do the ( ) first:

Page 68: 2.4 prime numbers and factors w

Basic Laws

For example, 2 1 1 2, and that ( 3 – 2 ) – 1 = 0 is different from 3 – ( 2 – 1 ) = 2. Thus when subtracting or dividing, we have to determine who is in the front and who is in the back.

However, subtraction and division are not commutative nor associative.

Distributive Law: a*(b ± c) = a*b ± a*c

. Example E. Do 5*( 3 + 4 ) two different ways and show the results are the same.

Do the ( ) first: 5*( 3 + 4 ) = 5*7 = 35,

Page 69: 2.4 prime numbers and factors w

Basic Laws

For example, 2 1 1 2, and that ( 3 – 2 ) – 1 = 0 is different from 3 – ( 2 – 1 ) = 2. Thus when subtracting or dividing, we have to determine who is in the front and who is in the back.

However, subtraction and division are not commutative nor associative.

Distributive Law: a*(b ± c) = a*b ± a*c

. Example E. Do 5*( 3 + 4 ) two different ways and show the results are the same.

Distribute the 5 first:

Do the ( ) first: 5*( 3 + 4 ) = 5*7 = 35,

Page 70: 2.4 prime numbers and factors w

Basic Laws

For example, 2 1 1 2, and that ( 3 – 2 ) – 1 = 0 is different from 3 – ( 2 – 1 ) = 2. Thus when subtracting or dividing, we have to determine who is in the front and who is in the back.

However, subtraction and division are not commutative nor associative.

Distributive Law: a*(b ± c) = a*b ± a*c

. Example E. Do 5*( 3 + 4 ) two different ways and show the results are the same.

Distribute the 5 first:

Do the ( ) first: 5*( 3 + 4 ) = 5*7 = 35,

5*( 3 + 4 ) = 5*3 + 5*4

Page 71: 2.4 prime numbers and factors w

Basic Laws

For example, 2 1 1 2, and that ( 3 – 2 ) – 1 = 0 is different from 3 – ( 2 – 1 ) = 2. Thus when subtracting or dividing, we have to determine who is in the front and who is in the back.

However, subtraction and division are not commutative nor associative.

Distributive Law: a*(b ± c) = a*b ± a*c

. Example E. Do 5*( 3 + 4 ) two different ways and show the results are the same.

Distribute the 5 first:

Do the ( ) first: 5*( 3 + 4 ) = 5*7 = 35,

5*( 3 + 4 ) = 5*3 + 5*4 = 15 + 20 = 35

Page 72: 2.4 prime numbers and factors w

Basic Laws

For example, 2 1 1 2, and that ( 3 – 2 ) – 1 = 0 is different from 3 – ( 2 – 1 ) = 2. Thus when subtracting or dividing, we have to determine who is in the front and who is in the back.

However, subtraction and division are not commutative nor associative.

Distributive Law: a*(b ± c) = a*b ± a*c

. Example E. Do 5*( 3 + 4 ) two different ways and show the results are the same.

Distribute the 5 first:

Do the ( ) first: 5*( 3 + 4 ) = 5*7 = 35,

5*( 3 + 4 ) = 5*3 + 5*4 = 15 + 20 = 35

the outcomes are the same as stated in the distributive law.

Page 73: 2.4 prime numbers and factors w

19. List the all the factors and the first 4 multiples of the following numbers. 6, 9, 10, 15, 16, 24, 30, 36, 42, 56, 60.

B. Calculate.1. 33 2. 42 3. 52 4. 53 5. 62 6. 63 7. 72

8. 82 9. 92 10. 102 11. 103 12. 104 13. 105

14. 1002 15. 1003 16. 1004 17. 112 18. 122

20. Factor completely and arrange the factors from smallest to the largest in the exponential notation: 4, 8, 12, 16, 18, 24, 27, 32, 36, 45, 48, 56, 60, 63, 72, 75, 81, 120.

21. 3 * 5 * 4 * 2 22. 6 * 5 * 4 * 323. 6 * 15 * 3 * 2

24. 7 * 5 * 5 * 4 25. 6 * 7 * 4 * 3 26. 9 * 3 * 4 * 4

27. 2 * 25 * 3 * 4 * 2 28. 3 * 2 * 3 * 3 * 2 * 4

29. 3 * 5 * 2 * 5 * 2 * 430. 4 * 2 * 3 * 15 * 8 * 4©

31. 24 32. 25 33. 26 34. 27 35. 28

36. 29 37. 210 38. 34 39. 35 40. 36

C. Multiply in two ways to find the correct answer.

© F. Ma

Page 74: 2.4 prime numbers and factors w

Exercise A. Do the following problems two ways. * Add the following by summing the multiples of 10 first. * Add by adding in the order.to find the correct answer. 1. 3 + 5 + 7 2. 8 + 6 + 2 3. 1 + 8 + 9 4. 3 + 5 + 15 5. 9 + 14 + 6 6. 22 + 5 + 8 7. 16 + 5 + 4 + 3 8. 4 + 13 + 5 + 79. 19 + 7 + 1 + 3 10. 4 + 5 + 17 + 311. 23 + 5 + 17 + 3 12. 22 + 5 + 13 + 2813. 35 + 6 + 15 + 7 + 14 14. 42 + 5 + 18 + 1215. 21 + 16 + 19 + 7 + 44 16. 53 + 5 + 18 + 27 + 2217. 155 + 16 + 25 + 7 + 344 18. 428 + 3 + 32 + 227 + 22Hence to add a list numbers, it's easier to add the ones that add to multiples of 10 first.Example D.

14 + 3 + 16 + 8 + 35 + 15 = 30 + 11 + 50 = 91