Properties of Exponents and Scientific Notation

By the end of this section, you will be able to:

Before you get started, take this readiness quiz.

  1. Simplify: (−2)(−2)(−2).

    If you missed this problem, review [link].

  2. Simplify: 8x24y.

    If you missed this problem, review [link].

  3. Name the decimal (−2.6)(4.21).

    If you missed this problem, review [link].

Simplify Expressions Using the Properties for Exponents

Remember that an exponent indicates repeated multiplication of the same quantity. For example, in the expression am,

the exponent m tells us how many times we use the base a as a factor.

First example: a raised to the power of m equals a times a times a times a and so on until you have multiplied m different factors of a together. Second example: the quantity negative 9 raised to the power of 5 equals negative 9 times negative 9 times negative 9 times negative 9 times negative 9, a total of 5 factors of negative 9. Let’s review the vocabulary for expressions with exponents.

Exponential Notation

The figure shows the letter a in a normal font with the label base and the letter m in a superscript font with the label exponent. This means we multiply the number a with itself, m times. This is read a to the mth

power.

In the expression am,

the exponent m tells us how many times we use the base a as a factor.

When we combine like terms by adding and subtracting, we need to have the same base with the same exponent. But when you multiply and divide, the exponents may be different, and sometimes the bases may be different, too.

First, we will look at an example that leads to the Product Property.

   
.    
{: valign=”top”} What does this mean?
.      
{: valign=”top”}    

. | {: valign=”top”}{: .unnumbered .unstyled summary=”The figure shows how to multiply exponentials with the same base. In the example we start with x raised to the power of 2 times x raised to the power of 3. This means the we are multiplying 2 factors of x with 3 factors of x for a total of 5 factors of x so the simplified result is x raised to the power of 5.” data-label=””}

Notice that 5 is the sum of the exponents, 2 and 3. We see x2·x3

is x2+3

or x5.

The base stayed the same and we added the exponents. This leads to the Product Property for Exponents.

Product Property for Exponents

If a is a real number and m and n are integers, then

am·an=am+n

To multiply with like bases, add the exponents.

Simplify each expression: y5·y6

2x·23x

2a7·3a.

* * *

     .
{: valign=”top”} Use the Product Property, am·an=am+n.

|    . | {: valign=”top”}| Simplify. |    . | {: valign=”top”}{: .unnumbered .unstyled summary=”To simplify the expression y to the power of 5 times y to the power of 6 we notice that the base numbers are the same allowing us to use the product property and add the exponents. The expression is equal to y to the power of the quantity 5 plus 6 which simplifies to y to the power of 11.” data-label=””}

* * *

     .
{: valign=”top”} Use the Product Property, am·an=am+n.

|    . | {: valign=”top”}| Simplify. |    . | {: valign=”top”}{: .unnumbered .unstyled summary=”To simplify the expression 2 to the power of x times 2 to the power of 3 x we notice that the base numbers are the same allowing us to use the product property and add the exponents. The expression is equal to 2 to the power of the quantity x plus 3 x which simplifies to 2 to the power of 4 x.” data-label=””}

* * *

   .
Rewrite, a=a1.    .
Use the Commutative Property and
use the Product Property, am·an=am+n.
   .
Simplify.    .

* * *

| |   . | {: valign=”top”}| Add the exponents, since bases are the same. |   . | {: valign=”top”}| Simplify. |   . | {: valign=”top”}{: .unnumbered .unstyled summary=”To simplify the expression d to the power of 4 times d to the power of 5 times d to the power of 2 we notice that the base numbers are the same allowing us to use the product property and add the exponents. The expression is equal to d to the power of the quantity 4 plus 5 plus 2 which simplifies to d to the power of 11.” data-label=””}

Simplify each expression:

b9·b8

42x·4x

3p5·4p

x6·x4·x8.

b17

43x

12p6


x18

Simplify each expression:

x12·x4

10·10x

2z·6z7

b5·b9·b5.

x16

10x+1

12z8


b19

Now we will look at an exponent property for division. As before, we’ll try to discover a property by looking at some examples.

Consider x5x2
and x2x3
     
{: valign=”top”} What do they mean? x·x·x·x·xx·x
  x·xx·x·x
     
{: valign=”top”} Use the Equivalent Fractions Property. x·x·x·x·xx·x
  x·x·1x·x·x
     
{: valign=”top”} Simplify. x3
  1x

| {: valign=”top”}{: .unnumbered .unstyled summary=”The figure shows two examples of simplifying with the exponent property of division. In the first example the expression is x to the power of 5 divided by x to the power of 2. This means we have 5 factors of x divided by 2 factors of x. Using the equivalent fractions property, we can cross off two factors of x from the numerator and two from the denominator just leaving 3 of the original 5 factors in the numerator. So the simplified expression is x to the power of 3. In the second example the expression is x to the power of 2 divided by x to the power of 3. This means we have 2 factors of x divided by 3 factors of x. Using the equivalent fractions property, we can cross off two factors of x from the numerator and two from the denominator just leaving 1 factor of x in the denominator. So the simplified expression is 1 divided by x.” data-label=””}

Notice, in each case the bases were the same and we subtracted exponents. We see x5x2

is x52

or x3

. We see x2x3

is or 1x.

When the larger exponent was in the numerator, we were left with factors in the numerator. When the larger exponent was in the denominator, we were left with factors in the denominator–notice the numerator of 1. When all the factors in the numerator have been removed, remember this is really dividing the factors to one, and so we need a 1 in the numerator. xx=1

. This leads to the Quotient Property for Exponents.

Quotient Property for Exponents

If a is a real number, a0,

and m and n are integers, then

aman=amn,m>nandaman=1anm,n>m

Simplify each expression: x9x7

31032

b8b12

7375.

To simplify an expression with a quotient, we need to first compare the exponents in the numerator and denominator.

* * *

Since 9>7,

there are more factors of x

in the numerator.

.  
{: valign=”top”} Use Quotient Property, aman=amn.

| . | {: valign=”top”}| Simplify. | . | {: valign=”top”}{: .unnumbered .unstyled summary=”Simplify the expression x to the power of 9 divided by x to the power of 7. Since 9 is greater than 7, there are 2 more factors of x in the numerator. Using the quotient property the division is equal to x to the power of the quantity 9 minus 7. This simplifies to x to the power of 2.” data-label=””}

* * *

Since 10>2,

there are more factors of 3

in the numerator.

.  
{: valign=”top”} Use Quotient Property, aman=amn.

| . | {: valign=”top”}| Simplify. | . | {: valign=”top”}{: .unnumbered .unstyled summary=”Simplify the expression 3 to the power of 10 divided by 3 to the power of 2. Since 10 is greater than 2, there are 8 more factors of 3 in the numerator. Using the quotient property the division is equal to 3 to the power of the quantity 10 minus 2. This simplifies to 3 to the power of 8.” data-label=””}

Notice that when the larger exponent is in the numerator, we are left with factors in the numerator.

* * *

Since 12>8,

there are more factors of b

in the denominator. .
{: valign=”top”} Use Quotient Property, aman=1anm.

| . | {: valign=”top”}| Simplify. | . | {: valign=”top”}{: .unnumbered .unstyled summary=”Simplify the expression b to the power of 8 divided by b to the power of 12. Since 12 is greater than 8, there are 4 more factors of b in the denominator. Using the quotient property the division is equal to 1 divided by b to the power of the quantity 12 minus 8. This simplifies to 1 divided by b to the power of 4.” data-label=””}

* * *

Since 5>3,

there are more factors of 3

in the denominator.

.  
{: valign=”top”} Use Quotient Property, aman=1anm.

| . | {: valign=”top”}| Simplify. | . | {: valign=”top”}| Simplify. | . | {: valign=”top”}{: .unnumbered .unstyled summary=”Simplify the expression 7 to the power of 3 divided by 7 to the power of 5. Since 5 is greater than 3, there are 2 more factors of 7 in the denominator. Using the quotient property the division is equal to 1 divided by 7 to the power of the quantity 5 minus 3. This simplifies to 1 divided by 7 to the power of 2 or 1 divided by 49.” data-label=””}

Notice that when the larger exponent is in the denominator, we are left with factors in the denominator.

Simplify each expression: x15x10

61465

x18x22

12151230.

x5

69

1x4


11215

Simplify each expression: y43y37

1015107

m7m15

98919.

y6

108

1m8


1911

A special case of the Quotient Property is when the exponents of the numerator and denominator are equal, such as an expression like amam.

We know,xx=1,

for any x(x0)

since any number divided by itself is 1.

The Quotient Property for Exponents shows us how to simplify amam.

when m>n

and when n<m

by subtracting exponents. What if m=n?

We will simplifyamam

in two ways to lead us to the definition of the Zero Exponent Property. In general, for a0:

In the first way we write a to the power of m divided by a to the power of m as a to the power of the quantity m minus m. This is equal to a to the power of 0. In the second way we write a to the power of m divided by a to the power of m as a fraction with m factors of a in the numerator and a factors of m in the denominator. Simplifying this we can cross of all the factors and are left with the number 1. This shows that a to the power of 0 is equal to 1. We see amam

simplifies to a0

and to 1. So a0=1.

Any non-zero base raised to the power of zero equals 1.

Zero Exponent Property

If a is a non-zero number, then a0=1.

If a is a non-zero number, then a to the power of zero equals 1.

Any non-zero number raised to the zero power is 1.

In this text, we assume any variable that we raise to the zero power is not zero.

Simplify each expression: 90

n0.

The definition says any non-zero number raised to the zero power is 1.

* * *

90 Use the definition of the zero exponent.1

* * *

n0 Use the definition of the zero exponent.1

To simplify the expression n raised to the zero power we just use the definition of the zero exponent. The result is 1.

Simplify each expression: 110

q0.

1 1

Simplify each expression: 230

r0.

1 1

Use the Definition of a Negative Exponent

We saw that the Quotient Property for Exponents has two forms depending on whether the exponent is larger in the numerator or the denominator. What if we just subtract exponents regardless of which is larger?

Let’s consider x2x5.

We subtract the exponent in the denominator from the exponent in the numerator. We see x2x5

is x25

or x−3.

We can also simplify x2x5

by dividing out common factors:

In the figure the expression x raised to the power of 2 divided by x raised to the power of 5 is written as a fraction with 2 factors of x in the numerator divided by 5 factors of x in the denominator. Two factors are crossed off in both the numerator and denominator. This only leaves 3 factors of x in the denominator. The simplified fraction is 1 divided by x to the power of 3. This implies that x−3=1x3

and it leads us to the definition of a negative exponent. If n is an integer and a0,

then an=1an.

Let’s now look at what happens to a fraction whose numerator is one and whose denominator is an integer raised to a negative exponent.

1an Use the definition of a negative exponent,an=1an.11an Simplify the complex fraction.1·an1 Multiply.an

This implies 1an=an

and is another form of the definition of Properties of Negative Exponents.

Properties of Negative Exponents

If n is an integer and a0,

then an=1an

or 1an=an.

The negative exponent tells us we can rewrite the expression by taking the reciprocal of the base and then changing the sign of the exponent.

Any expression that has negative exponents is not considered to be in simplest form. We will use the definition of a negative exponent and other properties of exponents to write the expression with only positive exponents.

For example, if after simplifying an expression we end up with the expression x−3,

we will take one more step and write 1x3.

The answer is considered to be in simplest form when it has only positive exponents.

Simplify each expression: x−5

10−3

1y−4

13−2.

* * *

x−5 Use the definition of a negative exponent,an=1an.1x5

* * *

10−3 Use the definition of a negative exponent,an=1an.1103 Simplify.11000

* * *

1y−4 Use the property of a negative exponent,1an=an.y4

* * *

13−2 Use the property of a negative exponent,1an=an.32 Simplify.9

Simplify each expression: z−3

10−7

1p−8

14−3.

1z3

1107

p8

64

Simplify each expression: n−2

10−4

1q−7

12−4.

1n2

110,000

q7


16

Suppose now we have a fraction raised to a negative exponent. Let’s use our definition of negative exponents to lead us to a new property.

(34)−2 Use the definition of a negative exponent,an=1an.1(34)2 Simplify the denominator.1916 Simplify the complex fraction.169 But we know that169is(43)2. This tells us that(34)−2=(43)2

To get from the original fraction raised to a negative exponent to the final result, we took the reciprocal of the base—the fraction—and changed the sign of the exponent.

This leads us to the Quotient to a Negative Power Property.

Quotient to a Negative Power Property

If a and b are real numbers, a0,b0

and n is an integer, then

and(ab)n=(ba)n

Simplify each expression: (57)−2

(xy)−3.

* * *

(57)−2 Use the Quotient to a Negative Exponent Property,(ab)n=(ba)n.Take the reciprocal of the fraction and change the sign of the exponent.(75)2 Simplify.4925

* * *

(xy)−3 Use the Quotient to a Negative Exponent Property,(ab)n=(ba)n.Take the reciprocal of the fraction and change the sign of the exponent.(yx)3 Simplify.y3x3

Simplify each expression: (23)−4

(mn)−2.

8116

n2m2

Simplify each expression: (35)−3

(ab)−4.

12527

b4a4

Now that we have negative exponents, we will use the Product Property with expressions that have negative exponents.

Simplify each expression: z−5·z−3

(m4n−3)(m−5n−2)

(2x−6y8)(−5x5y−3).

* * *

z−5·z−3 Add the exponents, since the bases are the same.z−53 Simplify.z−8 Use the definition of a negative exponent.1z8

* * *

(m4n−3)(m−5n−2) Use the Commutative Property to get likebases together.m4m−5·n−2n−3 Add the exponents for each base.m−1·n−5 Take reciprocals and change the signs of the exponents.1m1·1n5 Simplify.1mn5

* * *

(2x−6y8)(−5x5y−3) Rewrite with the like bases together.2(−5)·(x−6x5)·(y8y−3) Multiply the coefficients and add the exponentsof each variable.−10·x−1·y5 Use the definition of a negative exponent,an=1an.−10·1x·y5 Simplify.−10y5x

Simplify each expression:

z−4·z−5

(p6q−2)(p−9q−1)

(3u−5v7)(−4u4v−2).

1z9

1p3q3

12v5u

Simplify each expression:

c−8·c−7

(r5s−3)(r−7s−5)

(−6c−6d4)(−5c−2d−1).

1c15

1r2s8

30d3c8

Now let’s look at an exponential expression that contains a power raised to a power. See if you can discover a general property.

(x2)3 What does this mean?x2·x2·x2

| How many factors altogether? | . | {: valign=”top”}| So we have | . | {: valign=”top”}{: .unnumbered .unstyled summary=”The quantity x raised to the power of 2 raised to the power of 3 is written as x to the power of 2 times x to the power of 2 times x to the power of 2. Since each x to the power of 2 is 2 factors of x this is 6 factors of x so we have x to the power of 6.” data-label=””}

Notice the 6 is the product of the exponents, 2 and 3. We see that (x2)3

is x2·3

or x6.

We multiplied the exponents. This leads to the Power Property for Exponents.

Power Property for Exponents

If a is a real number and m and n are integers, then

(am)n=am·n

To raise a power to a power, multiply the exponents.

Simplify each expression: (y5)9

(44)7

(y3)6(y5)4.

* * *

  .
{: valign=”top”} Use the Power Property, (am)n=am·n.

| . | {: valign=”top”}| Simplify. | . | {: valign=”top”}{: .unnumbered .unstyled summary=”Simplify the quantity y to the power of 5 raised to the power of 9. Using the power property we multiply the exponents and get y to the power of 5 times 9 or y to the power of 45.” data-label=””}

* * *

| | . | {: valign=”top”}| Use the Power Property.          | . | {: valign=”top”}| Simplify. | . | {: valign=”top”}{: .unnumbered .unstyled summary=”Simplify the quantity 4 to the power of 4 raised to the power of 7. Using the power property we multiply the exponents and get 4 to the power of 4 times 7 or 4 to the power of 28.” data-label=””}

* * *

(y3)6(y5)4 Use the Power Property.y18·y20 Add the exponents.y38

Simplify each expression: (b7)5

(54)3

(a4)5(a7)4.

b35

512

a48

Simplify each expression: (z6)9

(37)7

(q4)5(q3)3.

z54

349

q29

We will now look at an expression containing a product that is raised to a power. Can you find this pattern?

(2x)3 What does this mean?2x·2x·2x We group the like factors together.2·2·2·x·x·x How many factors of 2 and ofx23·x3

Notice that each factor was raised to the power and (2x)3

is 23·x3.

The exponent applies to each of the factors! This leads to the Product to a Power Property for Exponents.

Product to a Power Property for Exponents

If a and b are real numbers and m is a whole number, then

(ab)m=ambm

To raise a product to a power, raise each factor to that power.

Simplify each expression: (−3mn)3

(−4a2b)0

(6k3)−2

(5x−3)2.

* * *

  .
{: valign=”top”} Use Power of a Product Property, (ab)m=ambm.

| . | {: valign=”top”}| Simplify. |  . | {: valign=”top”}{: .unnumbered .unstyled summary=”Given negative 3 m n in parentheses to the power of 3 we can use the power of a product property to write negative 3 to the power of 3 m to the power of 3 n to the power of 3. This simplifies to negative 27 m to the power of 3 n to the power of 3.” data-label=””}

* * *

(−4a2b)0 Use Power of a Product Property,(ab)m=ambm.(−4)0(a2)0(b)0 Simplify.1·1·1 Multiply.1

* * *

(6k3)−2 Use the Product to a Power Property,(ab)m=ambm.(6)−2(k3)−2 Use the Power Property,(am)n=am·n.6−2k−6 Use the Definition of a negative exponent,an=1an.162·1k6 Simplify.136k6

* * *

(5x−3)2 Use the Product to a Power Property,(ab)m=ambm.52(x−3)2 Simplify.25·x−6 Rewritex−6using,an=1an.25·1x6 Simplify.25x6

Simplify each expression: (2wx)5

(−11pq3)0

(2b3)−4

(8a−4)2.

32w5x5

1 116b12


64a8

Simplify each expression: (−3y)3

(−8m2n3)0

(−4x4)−2

(2c−4)3.

−27y3

1 116x8


8c12

Now we will look at an example that will lead us to the Quotient to a Power Property.

(xy)3 This meansxy·xy·xy Multiply the fractions.x·x·xy·y·y Write with exponents.x3y3

Notice that the exponent applies to both the numerator and the denominator.

We see that (xy)3

is x3y3.

This leads to the Quotient to a Power Property for Exponents.

Quotient to a Power Property for Exponents

If a

and b

are real numbers, b0,

and m

is an integer, then

(ab)m=ambm

To raise a fraction to a power, raise the numerator and denominator to that power.

Simplify each expression:

(b3)4

(kj)−3

(2xy2z)3

(4p−3q2)2.

* * *

    .
{: valign=”top”} Use Quotient to a Power Property, (ab)m=ambm.

|   . | {: valign=”top”}| Simplify. |   . | {: valign=”top”}{: .unnumbered .unstyled summary=”To simplify b divided by 3 in parentheses to the power of 4 we use the quotient to a power property. The result is b to the power of 4 divided by 3 to the power of 4. This simplifies to b to the power of 4 divided by 81.” data-label=””}

* * *

| | . | {: valign=”top”}| Raise the numerator and denominator to the power. | . | {: valign=”top”}| Use the definition of negative exponent. | . | {: valign=”top”}| Multiply. | . | {: valign=”top”}{: .unnumbered .unstyled summary=”To simplify k divided by j in parentheses to the power of negative 3 we use the quotient to a power property. The result is k to the power of negative 3 divided by j to the power of negative 3. Using the definition of negative exponent we have 1 divided by k to the power of 3 times j to the power of 3. This simplifies to j to the power of 3 divided by k to the power of 3.” data-label=””}

* * *

(2xy2z)3 Use Quotient to a Power Property,(ab)m=ambm.(2xy2)3z3 Use the Product to a Power Property,(ab)m=ambm.8x3y6z3

* * *

(4p−3q2)2 Use Quotient to a Power Property,(ab)m=ambm.(4p−3)2(q2)2 Use the Product to a Power Property,(ab)m=ambm.42(p−3)2(q2)2 Simplify using the Power Property,(am)n=am·n.16p−6q4 Use the definition of negative exponent.16q4·1p6 Simplify.16p6q4

Simplify each expression:

(p10)4

(mn)−7

(3ab3c2)4

(3x−2y3)3.

p410000

n7m7


81a4b12c8

27x6y9

Simplify each expression:

(−2q)3

(wx)−4

(xy33z2)2

(2m−2n−2)3.

−8q3

x4w4

x2y69z4


8n6m6

We now have several properties for exponents. Let’s summarize them and then we’ll do some more examples that use more than one of the properties.

Summary of Exponent Properties

If a and b are real numbers, and m and n are integers, then

Property Description
{: valign=”top”} ———-
Product Property am·an=am+n
     
{: valign=”top”} Power Property (am)n=am·n
     
{: valign=”top”} Product to a Power (ab)n=ambm
     
{: valign=”top”} Quotient Property aman=amn,a0
     
{: valign=”top”} Zero Exponent Property a0=1,a0
     
{: valign=”top”} Quotient to a Power Property (ab)m=ambm,b0
     
{: valign=”top”} Properties of Negative Exponents an=1an

and 1an=an

     
{: valign=”top”} Quotient to a Negative Exponent (ab)n=(ba)n

| {: valign=”top”}{: .unnumbered summary=”This table has two columns, labeled Property and Description. The Product Property states that a to the m times a to the n equals a to the m plus n. The Power Property states that a to the m raised to a power of n is a to the m times n. The Quotient Property states that a to the m divided by a to the n equals a to the m minus n when a is not equal to 0. The Zero Exponent Property states that a to the 0 power equals 1 when a is not equal to 0. The Properties of Negative Exponents states that a to the negative n equals 1 over a to the n and 1 over a to the negative n equals a to the n. The Quotient to a Negative Exponent states that a over b all raised to the negative n equals b over a all raised to the n.” data-label=””}

Simplify each expression by applying several properties:

(3x2y)4(2xy2)3

(x3)4(x−2)5(x6)5

(2xy2x3y−2)2(12xy3x3y−1)−1.

* * *

(3x2y)4(2xy2)3 Use the Product to a Power Property,(ab)m=ambm.(34x8y4)(23x3y6) Simplify.(81x8y4)(8x3y6) Use the Commutative Property.81·8·x8·x3·y4·y6 Multiply the constants and add the exponents.648x11y10

* * *

(x3)4(x−2)5(x6)5 Use the Power Property,(am)n=am·n.(x12)(x−10)(x30) Add the exponents in the numerator.x2x30 Use the Quotient Property,aman=1anm.1x28

* * *

(2xy2x3y−2)2(12xy3x3y−1)−1 Simplify inside the parentheses first.(2y4x2)2(12y4x2)−1 Use the Quotient to a Power Property,(ab)m=ambm.(2y4)2(x2)2(12y4)−1(x2)−1 Use the Product to a Power Property,(ab)m=ambm.4y8x4·12−1y−4x−2 Simplify.4y412x2 Simplify.y43x2

Simplify each expression:

(c4d2)5(3cd5)4

(a−2)3(a2)4(a4)5

(3xy2x2y−3)2(9xy−3x3y2)−1.

81c24d30

1a18


y15

Simplify each expression:

(a3b2)6(4ab3)4

(p−3)4(p5)3(p7)6

(4x3y2x2y−1)2(8xy−3x2y)−1.

256a22b24

1p39


2x3y10

Use Scientific Notation

Working with very large or very small numbers can be awkward. Since our number system is base ten we can use powers of ten to rewrite very large or very small numbers to make them easier to work with. Consider the numbers 4,000 and 0.004.

Using place value, we can rewrite the numbers 4,000 and 0.004. We know that 4,000 means 4×1,000

and 0.004 means 4×11,000.

If we write the 1,000 as a power of ten in exponential form, we can rewrite these numbers in this way:

4,000 4×1,000
4×103
     
{: valign=”top”} 0.004 4×11,000
4×1103
4×10−3

| {: valign=”top”}{: .unnumbered summary=”.” data-label=””}

When a number is written as a product of two numbers, where the first factor is a number greater than or equal to one but less than ten, and the second factor is a power of 10 written in exponential form, it is said to be in scientific notation.

Scientific Notation

A number is expressed in scientific notation when it is of the form

a×10nwhere1a<10andnis an integer.

It is customary in scientific notation to use as the ×

multiplication sign, even though we avoid using this sign elsewhere in algebra.

If we look at what happened to the decimal point, we can see a method to easily convert from decimal notation to scientific notation.

The figure shows two examples of converting from standard notation to scientific notation. In one example 4000 is converted to 4 times 10 to the power of 3. The decimal point in 4000 starts at the right and moves 3 places to the left to make the number 4. The 3 places moved make the exponent 3. In the other example, the number 0.004 is converted to 4 times 10 to the negative 3 power. The decimal point in 0.004 is moved 3 places to the right to make the number 4. The 3 places moved make the exponent negative 3. In both cases, the decimal was moved 3 places to get the first factor between 1 and 10.

The power of 10 is positive when the number is larger than 1: 4,000=4×103

The power of 10 is negative when the number is between 0 and 1: 0.004=4×10−3

To convert a decimal to scientific notation.
  1. Move the decimal point so that the first factor is greater than or equal to 1 but less than 10.
  2. Count the number of decimal places, n, that the decimal point was moved.
  3. Write the number as a product with a power of 10. If the original number is.
    • greater than 1, the power of 10 will be 10n.
    • between 0 and 1, the power of 10 will be 10n.
  4. Check.

Write in scientific notation: 37,000 0.0052.

* * *

The original number, 37,000, is greater than 1
so we will have a positive power of 10.
37,000
Move the decimal point to get 3.7, a number
between 1 and 10.
.
Count the number of decimal places the point
was moved.
.
Write as a product with a power of 10. .
Check:    3.7×1043.7×10,00037,000
.

* * *

The original number, 0.0052, is between 0
and 1 so we will have a negative power of 10.
0.0052
Move the decimal point to get 5.2, a number
between 1 and 10.
.
Count the number of decimal places the point
was moved.
.
Write as a product with a power of 10. .
Check:5.2×10−35.2×11035.2×110005.2×0.0010.0052
.

Write in scientific notation: 96,000 0.0078.

9.6×104

7.8×10−3

Write in scientific notation: 48,300 0.0129.

4.83×104


1.29×10−2

How can we convert from scientific notation to decimal form? Let’s look at two numbers written in scientific notation and see.

9.12×1049.12×10−4 9.12×10,0009.12×0.0001 91,2000.000912

If we look at the location of the decimal point, we can see an easy method to convert a number from scientific notation to decimal form.

The figure shows two examples of converting from scientific notation to standard notation. In one example 9.12 times 10 to the power of 4 is converted to 91200. The decimal point in 9.12 moves 4 places to the right to make the number 91200. In the other example, the number 9.12 times 10 to the power of -4 is converted to 0.000912. The decimal point in 9.12 is moved 4 places to the left to make the number 0.000912. In both cases the decimal point moved 4 places. When the exponent was positive, the decimal moved to the right. When the exponent was negative, the decimal point moved to the left.

Convert scientific notation to decimal form.
  1. Determine the exponent, n, on the factor 10.
  2. Move the decimal n places, adding zeros if needed.
    • If the exponent is positive, move the decimal point n places to the right.
    • If the exponent is negative, move the decimal point \|n\|

      places to the left.

  3. Check.

Convert to decimal form: 6.2×103

−8.9×10−2.

* * *

.
Determine the exponent, n, on the factor 10.
The exponent is 3.
Since the exponent is positive, move the
decimal point 3 places to the right.
.
Add zeros as needed for placeholders. .
.

* * *

.
Determine the exponent, n, on the factor 10. The exponent is −2.
Since the exponent is negative, move the
decimal point 2 places to the left.
.
Add zeros as needed for placeholders. .
.

Convert to decimal form: 1.3×103

−1.2×10−4.

1,300 −0.00012

Convert to decimal form: −9.5×104

7.5×10−2.

−950,000

0.075

When scientists perform calculations with very large or very small numbers, they use scientific notation. Scientific notation provides a way for the calculations to be done without writing a lot of zeros. We will see how the Properties of Exponents are used to multiply and divide numbers in scientific notation.

Multiply or divide as indicated. Write answers in decimal form: (−4×105)(2×10−7)

9×1033×10−2.

* * *

(−4×105)(2×10−7) Use the Commutative Property to rearrange the factors.−4·2·105·10−7 Multiply.−8×10−2 Change to decimal form by moving the decimal twoplaces left.−0.08

* * *

9×1039×10−2 Separate the factors, rewriting as the product of twofractions.93×10310−2 Divide.3×105 Change to decimal form by moving the decimal fiveplaces right.300,000

Multiply or divide as indicated. Write answers in decimal form:

(−3×105)(2×10−8)

8×1024×10−2.

−0.006

20,000

Multiply or divide as indicated. Write answers in decimal form:

; (−3×10−2)(3×10−1)

8×1042×10−1.

−0.009

400,000

Access these online resources for additional instruction and practice with using multiplication properties of exponents.

Key Concepts


To multiply with like bases, add the exponents.


To raise a power to a power, multiply the exponents.


To raise a product to a power, raise each factor to that power.


To raise a fraction to a power, raise the numerator and denominator to that power.


Property Description
{: valign=”top”} ———-
Product Property am·an=am+n
     
{: valign=”top”} Power Property (am)n=am·n
     
{: valign=”top”} Product to a Power (ab)n=ambm
     
{: valign=”top”} Quotient Property aman=amn,a0
     
{: valign=”top”} Zero Exponent Property a0=1,a0
     
{: valign=”top”} Quotient to a Power Property: (ab)m=ambm,b0
     
{: valign=”top”} Properties of Negative Exponents an=1an

and 1an=an

     
{: valign=”top”} Quotient to a Negative Exponent (ab)n=(ba)n

| {: valign=”top”}{: .unnumbered summary=”This table has two columns, labeled Property and Description. The Product Property states that a to the m times a to the n equals a to the m plus n. The Power Property states that a to the m raised to a power of n is a to the m times n. The Quotient Property states that a to the m divided by a to the n equals a to the m minus n when a is not equal to 0. The Zero Exponent Property states that a to the 0 power equals 1 when a is not equal to 0. The Properties of Negative Exponents states that a to the negative n equals 1 over a to the n and 1 over a to the negative n equals a to the n. The Quotient to a Negative Exponent states that a over b all raised to the negative n equals b over a all raised to the n.”}

Practice Makes Perfect

Simplify Expressions Using the Properties for Exponents

In the following exercises, simplify each expression using the properties for exponents.

d3·d6

45x·49x

2y·4y3

w·w2·w3

d9

414x

8y4

w6

x4·x2

89x·83

3z25·5z8

y·y3·y5

n19·n12

3x·36

7w5·8w

a4·a3·a9

n31

3x+6

56w6


a16

q27·q15

5x·54x

9u41·7u53


c5·c11·c2

mx·m3
mx+3
ny·n2
ya·yb
ya+b
xp·xq

x18x3

51253

q18q36

102103

x15

59

1q18

110

y20y10

71672

t10t40

8385

p21p7

41644

bb9

446

p14

412

1b8

145

u24u3

91595

xx7

10103

200

b0

1 1

130

k0

270

(270)

−1

−1

150

(150)

Use the Definition of a Negative Exponent

In the following exercises, simplify each expression.

a−2

10−3

1c−5

13−2

1a2

11000

c5

9

b−4

10−2

1c−5

15−2

r−3

10−5

1q−10

110−3

1r3

1100,000

q10


1,000

s−8

10−2

1t−9

110−4

(58)−2

(ba)−2

6425

a2b2

(310)−2

(2z)−3

(49)−3

(uv)−5

72964

v5u5

(72)−3

(3x)−3

(−5)−2

5−2

(15)−2

(15)−2

125

125

25

−25

5−3

(15)−3

(15)−3

(−5)−3

3·5−1

(3·5)−1

35

115

3·4−2

(3·4)−2

In the following exercises, simplify each expression using the Product Property.

b4b−8

(w4x−5)(w−2x−4)


(−6c−3d9)(2c4d−5)

1b4

w2x9

−12cd4

s3·s−7

(m3n−3)(m−5n−1)


(−2j−5k8)(7j2k−3)

a3·a−3

(uv−2)(u−5v−3)


(−4r−2s−8)(9r4s3)

1 1u4v5

−36r2j5

y5·y−5

(pq−4)(p−6q−3)


(−5m4n6)(8m−5n−3)

p5·p−2·p−4
1p
x4·x−2·x−3

In the following exercises, simplify each expression using the Power Property.

(m4)2

(103)6

(x3)−4

m8

1018

1x12

(b2)7

(38)2

(k2)−5

(y3)x

(5x)y

(q6)−8

y3x

5xy

1q48

(x2)y

(7a)b

(a9)−10

In the following exercises, simplify each expression using the Product to a Power Property.

(−3xy)2

(6a)0

(5x2)−2

(−4y−3)2

9x2y2

1 125x4


16y6

(−4ab)2

(5x)0

(4y3)−3

(−7y−3)2

(−5ab)3

(−4pq)0

(−6x3)−2

(3y−4)2

−125a3b3

1 136x6

9y8

(−3xyz)4

(−7mn)0

(−3x3)−2


(2y−5)2

In the following exercises, simplify each expression using the Quotient to a Power Property.

(p2)5

(xy)−6

(2xy2z)3

(4p−3q2)2

p532

x6y6

8x3y6z3


16p6q4

(x3)4

(ab)−5

(2xy2z)3

(4p−3q2)2

(a3b)4

(54m)−2

(2xy2z)3

(4p−3q2)2

a481b4

16m225

8x3y6z3

16p6q4

(x2y)3

(103q)−4

(2xy2z)3

(4p−3q2)2

In the following exercises, simplify each expression by applying several properties.

(5t2)3(3t)2

(t2)5(t−4)2(t3)7


(2xy2x3y−2)2(12xy3x3y−1)−1

1125t8

1t19

y43x2

(10k4)3(5k6)2

(q3)6(q−2)3(q4)8

(m2n)2(2mn5)4

(−2p−2)4(3p4)2(−6p3)2

16m8n22

4p6

(3pq4)2(6p6q)2

(−2k−3)2(6k2)4(9k4)2

Mixed Practice

In the following exercises, simplify each expression.

7n−1

(7n)−1

(−7n)−1

7n

17n

17n

6r−1

(6r)−1

(−6r)−1

(3p)−2

3p−2

−3p−2

19p2

3p2

−3p2

(2q)−4

2q−4

−2q−4

(x2)4·(x3)2
x14
(y4)3·(y5)2
(a2)6·(a3)8
x30
(b7)5·(b2)6
(2m6)3
2m18
(3y2)4
(10x2y)3
1,000x6y3
(2mn4)5
(−2a3b2)4
16a12b8
(−10u2v4)3
(23x2y)3
827x6y3
(79pq4)2
(8a3)2(2a)4
1,024a10
(5r2)3(3r)2
(10p4)3(5p6)2
25,000p24
(4x3)3(2x5)4
(12x2y3)4(4x5y3)2
x18y18
(13m3n2)4(9m8n3)2
(3m2n)2(2mn5)4
144m8n22
(2pq4)3(5p6q)2

(3x)2(5x)

(2y)3(6y)

45x3

48y4

(12y2)3(23y)2

(12j2)5(25j3)2

(2r−2)3(4−1r)2

(3x−3)3(3−1x5)4

12r4

13x11

(k−2k8k3)2
(j−2j5j4)3
1j3
(−4m−3)2(5m4)3(−10m6)3
(−10n−2)3(4n5)2(2n8)2
4000n12

Use Scientific Notation

In the following exercises, write each number in scientific notation.

57,000 0.026

340,000 0.041

34×104

41×10−3

8,750,000 0.00000871

1,290,000 0.00000103

1.29×106


103×10−8

In the following exercises, convert each number to decimal form.

5.2×102

2.5×10−2

−8.3×102

3.8×10−2

−830

0.038

7.5×106

−4.13×10−5

1.6×1010

8.43×10−6

16,000,000,000* * *

0.00000843

In the following exercises, multiply or divide as indicated. Write your answer in decimal form.

(3×10−5)(3×109)

7×10−31×10−7

(2×102)(1×10−4)

5×10−21×10−10

0.02 500,000,000

(7.1×10−2)(2.4×10−4)

6×1043×10−2

(3.5×10−4)(1.6×10−2)

8×1064×10−1

0.0000056 20,000,000

Writing Exercises

Use the Product Property for Exponents to explain why x·x=x2.

Jennifer thinks the quotient a24a6

simplifies to a4.

What is wrong with her reasoning?

Answers will vary.

Explain why 53=(−5)3

but 54(−5)4.

When you convert a number from decimal notation to scientific notation, how do you know if the exponent will be positive or negative?

Answers will vary.

Self Check

After completing the exercises, use this checklist to evaluate your mastery of the objectives of this section.

This table has 4 rows and 4 columns. The first row is a header row and it labels each column. The first column header is “I can…”, the second is “Confidently”, the third is “With some help”, and the fourth is “No, I don’t get it”. Under the first column are the phrases “simplify expressions using the properties for exponents.”, “use the definition of a negative exponent”, and “use scientific notation”. The other columns are left blank so that the learner may indicate their mastery level for each topic. After reviewing this checklist, what will you do to become confident for all goals?

Glossary

Product Property
According to the Product Property, a to the m times a to the n equals a to the m plus n.
Power Property
According to the Power Property, a to the m to the n equals a to the m times n.
Product to a Power
According to the Product to a Power Property, a times b in parentheses to the m equals a to the m times b to the m.
Quotient Property
According to the Quotient Property, a to the m divided by a to the n equals a to the m minus n as long as a is not zero.
Zero Exponent Property
According to the Zero Exponent Property, a to the zero is 1 as long as a is not zero.
Quotient to a Power Property
According to the Quotient to a Power Property, a divided by b in parentheses to the power of m is equal to a to the m divided by b to the m as long as b is not zero.
Properties of Negative Exponents
According to the Properties of Negative Exponents, a to the negative n equals 1 divided by a to the n and 1 divided by a to the negative n equals a to the n.
Quotient to a Negative Exponent
Raising a quotient to a negative exponent occurs when a divided by b in parentheses to the power of negative n equals b divided by a in parentheses to the power of n.

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