UNIT 4: Prealgebra in a Technical World
4.2 Multiplying and Dividing Decimals
SWBAT 1. Multiply decimals.
2. Divide decimals.
3. Multiply and divide powers of ten.
4. Multiply and divide signed decimals.
5. Multiply and divide using scientific notation.
In grade school we learned to move the decimal point when we calculated products and
quotients. Using the calculator, we will no longer need to multiply and divide each of the digits,
but we will still be the one responsible for checking the place value of our answers. To be
accurate and efficient, we need to work our calculators wisely when we multiply and divide.
Keying in long strings of zeros is not a wise use of a calculator; in fact, it is a sure way to
make mistakes! With scientific notation and powers of ten, we do not have to key these zeros
into our calculator; we can calculate the place value of our products and quotients using mental
math.
In this section we study multiplying and dividing signed decimals
using powers of ten and scientific notation.
Multiplying Decimals
When most of us think about multiplying decimals, we think about money. When we
multiply with money, we can still round to the leading digit to make estimates.
Example 1: Working weekend nights at the emergency room, Bernie receives differential pay
of 1.75 times his daytime wages. If the daytime wage is $325.89 per shift, what will Bernie earn
for working a weekend night?
Think it through:
Understand: We need to multiply the weekend night differential pay by the
daytime wages.
303
304
SECTION 4.2: Multiplying and Dividing Decimals
Plan: We need to multiply. Our estimate is $300 ∙2 = $600.
Solve:
$325.89 ∙ 1.75 Write the expression.
≈ 300 ∙ 2 = $600 Estimate by rounding to leading digit.
325.89 ∙ 1.75 = $570.3075 Use a calculator and notice that this
fits our estimate.
≈ $570.31 Round to the nearest cent since
Bernie’s wages are paid in dollars
and cents.
ANSWER: Bernie will be paid $570.30 or $570.31 for the weekend night shift.
When working with money, our factors may have long decimal fractions. We do not round
these until we are finished with all of our calculations.
Example 2: Josephine County has 19 tax districts. For one Grants Pass district, the total
property tax rate was $13.9592 per thousand dollars of assessed property value for the
2011-20012 tax year. What are the taxes John would pay on a house assessed for tax purposes
at $218,345 in this district?
Think it through: Understand: We need to find the taxes on this property. The taxes are not
charged per dollar, “but per thousand dollars.” That means we will think of
$218,345 as “$218.345 thousand.” We can then multiply the tax rate by the
thousands of dollars of assessed value to find the total tax amount.
Plan: Estimate by rounding both the rate and the value of the home. Use a
calculator to multiply the more exact answer. Round the final answer so that
it is useful.
Solve: Estimate $200 ∙ 14 = $2,800 and this will be low.
218.345 ∙ 13.9592 = 3047.921524 ≈ $3047.92
Check: Our calculated answer of $2653.26 is reasonably close to $2,400.
ANSWER: John would pay $3,047.92 property taxes for a house in this district.
UNIT 4: Prealgebra in a Technical World
While our calculations gave us fractions of a cent, we round these results to a
reasonable number of decimal places for applications. For the last application, we are only
going to pay our taxes to the cent.
 Check Point 1
Caleb’s Medford home was assessed for tax purposes at $218,000. His total property tax rate is
$14.4672 per thousand dollars of assessed property value. How much will he pay in property
taxes? Answer using reasonable digits.
Dividing Decimals
To divide we will again use our calculators. First, we make reasonable estimates so that
we can quickly check our results. We round our results to numbers that make sense.
Example 3: Johannes' gross pay (before deductions) is $249.10. He makes $9.40 an hour, but
he is not sure how many hours are on this pay check. He decides to divide to find out.
Think it through: Hours is the missing factor, so divide gross pay ($249.10) by the rate of pay
($9.40).
249.10 ≈ 250 and 9.40 ≈ 10
250 ÷ 10 = 25
249.10 ÷ 9.4 = 26.5
Round and estimate.
Estimate 25 hours.
Use a calculator.
The calculated result fits the estimate, so Johannes accepts it.
ANSWER: Johannes was paid for 26.5 hours on this paycheck.
To estimate when we divide, we look for a close multiplication fact, then we find the
missing factor. For instance 76 ÷ 9 ≈ 72 ÷ 9 so 76 ÷ 9 ≈ 8.
305
306
SECTION 4.2: Multiplying and Dividing Decimals
Example 4: Chanterelle borrowed $5,500 for college from her family. They agreed to give her
the money if she paid them back $6,500 within the first three years after she finishes college. If
Chanterelle decides to pay back the loan by making equal payments for the first 36 months she
is out of college, what will she pay each month?
Think it through: Understand: The payment amount is the missing factor, so divide.
Plan: Round the money owed and months to create a division fact that we
can calculate mentally. Then use a calculator for the exact answer.
Solve:
Chanterelle
chooses this
division fact,
but there are
others.
6500 ÷ 36
6800 ÷ 40 = 680 ÷ 4 = 170
6500 ÷ 36 = 180.5555 …
Write the expression.
Estimate by rounding to a division
fact.
Use a calculator.
Check: The calculated result fits the estimate, so Chanterelle accepts it.
ANSWER: Chanterelle will round up and pay for $180.56 each month for 36 months.
 Check Point 2
Show your rounding and estimate first, and then divide. Stan’s entire annual bill for Rogue
Community College tuition and fees is $5,268.90. He wants to divide this up into 9 monthly
payments. How much is each payment?
Estimate: _____________________________________________________________________
Exact answer: __________________________________________________________________
Multiplying and Dividing Powers of Ten
Because exponents tell us how many times a base is multiplied by itself, when we
multiply by powers of ten we will end up with a different power of ten. See if you can find the
pattern in these next two examples before you read the rules. The first example shows what
happens when we multiply powers of ten.
UNIT 4: Prealgebra in a Technical World
Example 5: Multiply these:
a. 102 ∙ 105
b. 10−3 ∙ 10−1
c. 10−4 ∙ 101
d. 10−3 ∙ 105
Think it through: The bases are the same and we are multiplying, add the exponents.
a. 102 ∙ 105 = (10 ∙ 10) ∙ (10 ∙ 10 ∙ 10 ∙ 10 ∙ 10) = 107
1
1
1
1
1
b. 10−3 ∙ 10−1 = (10 ∙ 10 ∙ 10) ∙ 10 = 10,000 = 10−4
1
1
1
1
1
1
1
10
c. 10−4 ∙ 101 = (10 ∙ 10 ∙ 10 ∙ 10) ∙ 10 = 1,000 = 10−3
d. 10−3 ∙ 105 = (10 ∙ 10 ∙ 10) ∙ 10 ∙ 10 ∙ 10 ∙ 10 ∙ 10 =
100,000
1,000
=
100
1
= 102
RULE: To multiply powers of ten, add the exponents and keep ten as the base.
The next example shows what happens when we divide powers of ten. Again see if you
can find the rule before it is given.
Example 6: Divide these:
a. 102 ÷ 105
b. 10−2 ÷ 10−3
c. 10−4 ÷ 101
d. 10−3 ÷ 105
Think it through: The bases are the same and we are dividing, subtract the exponents.
10∙10
a. 102 ÷ 105 = (10 ∙ 10) ÷ (10 ∙ 10 ∙ 10 ∙ 10 ∙ 10) = 10∙10∙10∙10∙10 = 10−3
1
1
1
1
1
1
1
b. 10−2 ÷ 10−3 = (10 ∙ 10) ÷ (10 ∙ 10 ∙ 10) = (10 ∙ 10) ∙ (10 ∙ 10 ∙ 10) = 101
1
1
1
1
1
1
1
1
1
1
1
1
c. 10−4 ÷ 101 = (10 ∙ 10 ∙ 10 ∙ 10) ÷ 10 = 1,000 ∙ 10 = 10−5
d. 10−3 ÷ 105 = (10 ∙ 10 ∙ 10) ÷ (10 ∙ 10 ∙ 10 ∙ 10 ∙ 10)
1
1
1
1
1
1
= (10 ∙ 10 ∙ 10) ∙ (10 ∙ 10 ∙ 10 ∙ 10 ∙ 10) = 100,000,000 = 10−8
RULE: To divide powers of ten, subtract the exponents and keep ten as the base.
307
308
SECTION 4.2: Multiplying and Dividing Decimals
 Check Point 3
Multiply.
a. 106 ∙ 10−4
b. 10−3 ∙ 10−1
Divide.
c. 106 ÷ 10−4
d. 10−3 ÷ 10−1
Multiplying and Dividing Signed Decimals
Decimals are fractions. When we multiply and divide, it may be easier to estimate and
calculate using their fractional equivalents or it may be easier using scientific notation. When
we multiply and divide decimals, the rules of signs apply.
Example 7: Multiply.
a. (9.2) ∙ (−0.008)
Think it through: Use fractions to multiply in order to see the power of ten.
9
−8
−72
( )∙ (
)
= 0.072
1
1000
1000
9.2 (−8)
(9.2) ∙ (−0.008) =
∙
1 1000
−73.6
1000
Estimate using leading digits and
decimal fractions.
Regroup using the properties.
Multiply the numerators.
−0.0736 Rewrite as a decimal. The 3 is in the
thousandths place.
ANSWER: (𝟗. 𝟐) ∙ (−𝟎. 𝟎𝟎𝟖) = −𝟎. 𝟎𝟕𝟑𝟔
UNIT 4: Prealgebra in a Technical World
b. (87.24 ) ∙ −0.0000003
Think it through: Use scientific notation to multiply to make the calculation easier.
−(87.24 ∙ 0.0000003) Write the expression showing that the
product is negative.
1 ) (3
−7 )
−(8.724 x 10 ∙
x 10
Rewrite using scientific notation.
−(8.724 ∙ 3) x (101 ∙ 10−7 ) Use the commutative property to
regroup.
1
−7
Estimate by rounding to leading digit.
 − (9 ∙ 3) x (10 ∙ 10 )
 − 27 x 10−6
−(26.172 )x ( 10−6 ) Use the calculator to multiply 8.724 ∙ 3.
Add the exponents for the power of ten.
Move the decimal point 6 powers of ten
= −0.000026172
to the left (smaller).
ANSWER: −𝟖𝟕. 𝟐𝟒 ∙ 𝟎. 𝟎𝟎𝟎𝟎𝟎𝟎𝟑 = −𝟎. 𝟎𝟎𝟎𝟎𝟐𝟔𝟏𝟕𝟐
 Check Point 4
Multiply.
a. (−0.074 ) ∙ (−0.000805)
b. (0.0125) ∙ (−0.0025)
When working with application problems, we round our final answer to a reasonable place
value.
Example 8: The children’s dosage for medications is sometimes based on weight in kilograms.
To change pounds to kilograms, we can use the formula 𝑘 = 0.4536 ∙ 𝑝 where 𝑘 is the kilogram
measure and 𝑝 is the weight in pounds. How many kilograms does a 62-pound child weigh?
Think it through: Understand: We need to convert the weight to pounds using a formula.
Plan: Use the formula 𝑘 = 0.4536 ∙ 𝑝
309
310
SECTION 4.2: Multiplying and Dividing Decimals
Solve:
𝑘 = 0.4536 ∙ 62 Write the formula.
1
≈ 2 ∙ 62 = 31
Estimate using a close fraction.
0.4536 ∙ 62 = 28.1232 Use a calculator and notice that this
fits our estimate.
Because the pounds were in whole
≈ 28 kg numbers, round to whole kilograms.
Check: Because 0.4536 is about ½, the answer should be a bit less than
31 pounds. Since 28 is close to 31, we accept this answer.
ANSWER: A child who weighs 62 lbs. weighs about 28 kg.
 Check Point 5
Roger is machining a fine jewelry fitting part that has a length of 0.25” and a width of 0.125.”
What is its area?
When we divide using decimal fractions like 0.14 ÷ 0.007, we change the division
problem to one that gives us an equivalent quotient while dividing by a whole number. We
used this process for long division with paper and pencil.
For 0.14 ÷ 0.007 we wrote:
We moved the decimal point:
Only then did we fill in a zero and divide:
We can also use decimal fractions to see why we have equivalent quotients when we
move the decimal point in a division problem.
UNIT 4: Prealgebra in a Technical World
0.14
We can also look at this problem another way. If we write our division 0.007 , then we
can multiply by a fraction equal to one that gives whole numbers in both the numerator and
denominator. For this fraction,
1,000
1,000
0.14
1,000
140
is a great choice. So we have 0.007 ∙ 1,000 = 7 . Next we
can divide using whole numbers.
These expressions, 0.14 ÷ 0.007 ,
0.14
0.007
,
140
7
, and 140 ÷ 7 are all equivalent
expressions. They simplify to the same number.
RULE: Every decimal division problem can be rewritten as an equivalent fraction
with integers in both numerator and denominator.
Example 9: Divide.
a. (−9.2) ÷ (0.008)
Think it through: The quotient will be negative. Rewrite to divide by an integer.
(−9.2) ÷ (0.008) = −9200 ÷ 8 Multiply each number by 1,000
to divide by an integer.
−8800 ÷ 8 ≈ −1,100
Round to a convenient division
fact and estimate.
−9200 ÷ 8 = −1,150
Divide. The result fits the
estimate.
ANSWER: (−𝟗. 𝟐) ÷ (𝟎. 𝟎𝟎𝟖) = −𝟏, 𝟏𝟓𝟎
b. (−0.001224 ) ÷ (−0.13)
Think it through: The quotient will be positive. Rewrite to divide by an integer.
(−0.001224) ÷ (−0.13) = 0.1224 ÷ 13 Multiply each number by
10 to divide by an integer.
Round to a convenient
≈ 0.1300 ÷ 13 = 0.01
division fact and estimate.
311
312
SECTION 4.2: Multiplying and Dividing Decimals
≈ 0.0094153
Use the calculator to
divide.
ANSWER: (−𝟎. 𝟎𝟎𝟏𝟐𝟐𝟒 ) ÷ (−𝟎. 𝟏𝟑) ≈ 𝟎. 𝟎𝟎𝟗𝟒𝟏𝟓𝟑𝟖𝟓. Again this answer is
noteworthy, because we do not have an exact answer. If we round to three
decimal places, the result is (−𝟎. 𝟎𝟎𝟏𝟐𝟐𝟒 ) ÷ (−𝟎. 𝟏𝟑) ≈ 𝟎. 𝟎𝟎𝟗.

Check Point 6
Divide.
a. (−2.125 ) ÷ (−0.75)
b. (0.3125) ÷ (−2.5)
Computers, calculators and all computing technologies have a limit to the number of
characters that can be displayed on a screen. If your calculator’s limit is reached, the result
displayed is an estimate, not an exact value.

Check Point 7
So that we can see many of the ways calculators display results when they reach their limits for
decimal notation, please take part in collecting data for our math class. Use your calculator to
multiply the following problems and bring your answer to class.
a. The 2007 average income per person in the U.S. was about $34,000 according to the U.S.
Census Bureau. In 2007 the average population of the U.S. was about 301,000,000 people.1
Multiply these two numbers to find the total income in the U.S.
Write your calculator result: ___________________________________________________
b. The rectangular surface area of a nanofiber captures the sun’s energy in a solar cell. This
nanofiber has a length of 0.000 000 5 meters and a width of 0.000 000 05 meters. What is
the area of the fiber that is exposed to the sun?
Write your calculator result: ___________________________________________________
1
http://www.census.gov/compendia/statab/brief.html
UNIT 4: Prealgebra in a Technical World
Even if we have not yet reached the calculator’s limit, we eliminate mistakes when we
keep track of place value rather than writing long strings of zeros. The fewer key strokes we
use on our calculator, the fewer our key stroke errors.
To use a calculator to multiply and divide long decimals, we often must enter these
numbers in our calculator using powers of ten because we have reached the limit of the place
value display of our calculator. Even when we have a choice of methods, we use scientific
notation with our calculators to avoid leaving out (or adding extra) zeros as we punch keys.
Multiplying and Dividing Using Scientific Notation
Example 10: Given the information about the 2011 population and the average income per
person in Check Point 7a, calculate the total personal income in the U.S.A. for 2011 using
scientific notation with a calculator.
Think it through: Understand: We need to multiply to find our solution.
Plan: Use scientific notation to multiply decimals in our calculator and apply
powers of ten using mental math.
Solve:
(3.11 x 108 ) ∙ (4.2 x 104 )
(3.11 ∙ 4.2) ∙ (108 ∙ 104 )
≈ 12 x 1012 = 1013
13.062 x 1012
13,062,000,000,000
Write the multiplication problem
using scientific notation.
Use the commutative property to
regroup.
Estimate
Use the calculator for 3.11 ∙ 4.2 .
Add the exponents mentally.
Multiply.
ANSWER:  Our answer fits our estimate.
The total income in the U.S. for 2011 is about $13,062,000,000,000. This is
13.062 trillion dollars!
313
314
SECTION 4.2: Multiplying and Dividing Decimals
When we divide large numbers, we can write this division as a fraction and eliminate
factors of 10. For instance, if we want to divide the approximate U.S. national debt by the
number of people in the U.S., we can use fractions:
15,000,000,000,000
300,000,000
or we can write this
using powers of 10 and division, 15 x 1012 ÷ (3 x 108 ).
Using a fraction we divide factors of 10:
15,000,000,000,000
300,000,000
=
150,000
3
= $50,000.
Using scientific notation we regroup and subtract powers of ten:
12 x 1012 ÷ (3 x 108 ) = (12 ÷ 3) x (1012 ÷ 108 ) = 5 x 104 = $50,000.
We can use powers of ten to simplify our calculations so that when we need to use a
calculator, we use the fewest key strokes possible. Fewer key strokes mean less chance of error.
If we can think a problem through and eliminate the calculator altogether, this is even better.
Example 11: Planners are already working to replace petroleum when we run out. Their
planning is based on the estimates for the number of barrels of crude oil left on the planet.
These estimates run between 1.2 trillion and 2 trillion barrels. The high estimate was made in
2011 by Chevron CTO Don Paul, and this is the one we will use.2
The world population was estimated at 7,000,000,000 people in 2012. Using these
figures, what was the average number of barrels of crude oil per person left on Earth in 2012?
Think it through: Understand: We need to divide the barrels of oil left by the people on the
planet.
Plan: We will use the highest estimate for the barrels of oil remaining in the
ground. 2 trillion is 2.0 x 1012 since a trillion is 1012 . A billion is 109 , so the
world population can be written as 6.8 x 109 . We divide these to find the
unit rate, the barrels per person.
(2.0 x 1012 ) ÷ (7.0 x 109 ) Write the problem using
powers of ten.
2
http://news.cnet.com/8301-10784_3-9803819-7.html
UNIT 4: Prealgebra in a Technical World
Solve:
(2.0 ÷ 7.0 ) x (1012 ÷ 109 ) Use the properties to regroup.
Divide 9 factors of 10 away
from the powers of ten.
(0.285714285) x 103 Use the calculator to divide
the significant figures.
285.714285 Use powers of ten to move the
decimal point 3 to the right.
≈ 285 barrels Round up to the barrel.
(2.0 ÷ 7.0 ) x 103
1
Check: 1012 ÷ 109 = 103 = 1,000, and 2.0 ÷ 7.0 ≈ 2 ÷ 6 = 3 , and
1
3
(1,000) ≈ 300. Because 285 ≈ 300, we accept our answer.
ANSWER: If we divide the oil evenly, each person on the planet has about 285 barrels
of crude oil left.
(You may be interested to know that each barrel of oil yields between 19 and
20 gallons of gasoline3. According to the information used and our results,
we have less than 5700 gallons of gasoline per person left on Earth).
 Check Point 8
NASA has already sent robotic missions to Mars and has other Martian missions planned. Mars
is 1.52 Astronomical Units from Earth. An astronomical unit is the distance from Earth to our
sun. Astronomical unit is abbreviated AU and is equal to 92,955,800 miles. How many miles is it
from Earth to Mars? (Round your answer to the nearest million).
Estimate: _____________________________________________________________________
Answer: ______________________________________________________________________
3
http://tonto.eia.doe.gov/ask/gasoline_faqs.asp
315
316
SECTION 4.2: Multiplying and Dividing Decimals
 Check Point 9
The U.S. health care system spent $2.2 trillion on health care in 20084. How much money was
this for each of the 306 million people in the United States in 2008?
Estimate: _____________________________________________________________________
Answer: ______________________________________________________________________
4
http://money.cnn.com/2009/08/10/news/economy/healthcare_money_wasters/
UNIT 4: Prealgebra in a Technical World
4.2 Exercise Set
Name _______________________________
Skills
Estimate and then use paper and pencil or mental math strategies to find the exact answer.
For example 8.4 ∙ 0.05 = 4.2 ∙ 0.1 ≈ 0.4 uses the method of halving and doubling.
Do not use a calculator.
1. (9.7)(7.8)
Est.____________
Est.____________
Ans.___________
Ans.___________
3. (0.48)(0.64)
5.
2. (0.071)(6.8)
4. (6.94)(0.04)
Est.____________
Est.____________
Ans.___________
Ans.___________
(0.007)(17,400)
6. (0.039)(8.006)
Est.____________
Est.____________
Ans.___________
Ans.___________
7. (8.1)(0.0074)
8. (2.05)(−6.1)
Est.____________
Est.____________
Ans.___________
Ans.___________
9. (−0.22)(−0.33)
10. (−10.3)(−0.01)
Est.____________
Est.____________
Ans.___________
Ans.___________
11. −0.005(−6.12)
12. (−44.44)(−3.1)
Est.____________
Est.____________
Ans.___________
Ans.___________
13. (9.99)(−99.99)
14. (−0.44)0.0044
Est.____________
Est.____________
Ans.___________
Ans.___________
317
318
SECTION 4.2: Multiplying and Dividing Decimals
Estimate the quotient using multiplication facts and place value. Then divide by hand and
show your work on a paper that you staple to this assignment. Round your hand-calculated
answer to the nearest thousandth.
Estimate
Answer
15. 9.1 ÷ 0.3
16. 0.099 ÷ 0.9
17. 0.92 ÷ 0.02
18. 6.16 ÷ 0.08
19. −84.32 ÷ 0.05
20. 0.32 ÷ (−8.2)
21. −12.33 ÷ (−0.44)
22. −14.2 ÷ (−70.4)
Round to the nearest multiplication fact, divide and complete your estimate using place value.
Then divide using your calculator. Round your calculator answer to the nearest thousandth.
Estimate
Answer
23. 95.703 ÷ 18.6
24. −0.830 ÷ 7.005
25. 7.8 ÷ 0.005
26. 0.62 ÷ 0.0028
27. 2.81 ÷ −0.009
28. 99.9 ÷ 0.03
29. 1.26 ÷ 0.061
30. −.0042 ÷ 0.071
31. 1.49 ÷ 7.23
32. 0.008 ÷ 0.0023
33. −17.04 ÷ −0.8
34. 0.43 ÷ 4.06
For problems 35 - 46 multiply or divide by the given power of 10. No calculators are necessary.
UNIT 4: Prealgebra in a Technical World
35.
37.
39.
41.
43.
45.
61.2 ∙ 105 =____________________ 36.
−0.363 ∙ 103 =_________________ 38.
10.6 ∙ 104 =____________________ 40.
51,207 ÷ 104 =_________________ 42.
−4.6 ÷ 10−2= ___________________ 44.
12,355 ÷ 10−5 =________________ 46.
Applications
0.004 ∙ 104 =___________________
−2.5 ∙ 102 =____________________
0.00452 ∙ 10−5 =________________
0.25 ÷ 10−2 =__________________
−33.7 ÷ 10−3 =_________________
−0.2 ÷ 10−4 =__________________
UPS
47. Use the City of Grants Pass 2007 Tax table on page 286 for a and b.
a. How much are the total property taxes for a GP home assessed at $249,000?
b. How many of these tax dollars would go to support Rogue Community College?
48. a. How much are the total property taxes for a GP home assessed at $152,000?
b. How many of these tax dollars would go to support School District 7?
49. Answer the questions below using the
table on the right.
a. How much are the total property
taxes for a San Francisco home
assessed at $249,000?
b. What are the total property taxes
for a San Francisco home assessed
at $2.49 million?
2011 City and County of San Francisco Tax
Rates for $100 of Assessed Property Value
SF Community College
SF Unified School District
City and County of S. F.
Library Preservation Fund
SF Children's Fund
Open Space Acquisition
Bond Interest & Redemption
Superintendent of Schools
General Obligation Bonds
Bay Area Air Quality District
0.074
0.3237
0.565900123
0.025
0.03
0.025
0.1147
0.001
0.0063
0.00208539
Total Tax Assessment
(per $100)
50.
If a person owned a San Francisco home assessed at $2.3 million, how much of this
property tax money goes to the Library Preservation Fund? How much of this property
tax money goes to the Bay Area Air Quality District?
319
320
SECTION 4.2: Multiplying and Dividing Decimals
51.
Alexis is getting a cost of living raise on her next paycheck. If her current salary is
$1490.61 and the cost of living has increased by a factor of 0.015, how much will Alexis's
raise be?
52.
Oswald is getting a step raise in pay after working for his company for one year. His
current monthly salary is $4,230, and his salary will increase by a factor of 0.045. What is
his new salary?
53. In the checkpoints for this lesson you found the distance to Mars in astronomical units
(AU). Find the distances from the sun to other planets in miles and complete this table:
Planet
Number of
astronomical units
(AU)
Mercury
0.39
Venus
0.72
Earth
1
Mars
1.52
Jupiter
5.2
Saturn
9.54
Uranus
19.18
Neptune
30.06
Distance to sun in
miles
Distance to sun in
miles in scientific
notation
92,955,800
9.296 x 107
* Pluto is no longer considered a planet.
54.
The following table lists 2 estimates of the U.S. debt. The first is an estimate of the total
indebtedness of all of us who live in the U.S. This first estimate includes personal,
business and financial sector debt. The second is the U.S. national debt which is owed by
us through our government. If the U.S. population is about 314 million in 2012, how
much would each of us have to pay to get ourselves out of these total debts?
Estimate of U.S. Debt
$52,000,000,000,000
$15,980,000,000,000
Debt in Scientific Notation
Amount Owed per Person