Name
LESSON
Date
Class
Challenge
1-2 Money Grows
If an investment of $50 doubles in value, your investment will be
worth $50 • 2 $100.
If it doubles again, your investment will be worth $50 • 2 • 2 $200.
You can also write this as $50 • 22 $200.
If your money doubles a third time, it will be worth $50 • 23 $400.
Write the correct answer.
1. If you invest $400, how much will it
be worth if it doubles in value twice?
2. If an investment of $550 doubles in
value twice, how much will it be
worth?
3. If you invest $75, how much will it be
worth if it doubles in value 4 times?
4. If you invest $125, how much will it be
worth if it doubles in value 4 times?
5. If an investment of $75 triples in
value 3 times, how much will it be
worth?
6. If an investment of $125 triples in
value 4 times, how much will it be
worth?
When Jasmine turned 13, she started saving $5 per month until she
turned 18. She then invested her total savings so that it doubled in
value every 7 years.
7. How much money did Jasmine save by the time she turned 18?
8. How many times will her investment double from age 18 to age 60?
9. How much will Jasmine’s investment be worth when she turns 60?
When Jake turned 13, he started saving $1.50 per week until he
turned 19. He then invested his total savings so that it tripled in
value every 12 years.
10. How much money did Jake save by the time he turned 19?
11. How many times will his investment triple from age 19 to age 55?
12. How much will Jake’s investment be worth when he turns 55?
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
17
Holt Mathematics
Problem Solving
1-2 Exponents
Challenge
1-2 Money Grows
LESSON
LESSON
Write the correct answer.
If an investment of $50 doubles in value, your investment will be
worth $50 • 2 $100.
1. The cells of the bacteria E. coli can
double every 20 minutes. If you begin
with a single cell, how many cells can
there be after 4 hours?
If it doubles again, your investment will be worth $50 • 2 • 2 $200.
You can also write this as $50 • 22 $200.
If your money doubles a third time, it will be worth $50 • 23 $400.
2. The population of metropolitan
Orlando, Florida, has doubled about
every 16 years since 1960. In 2000,
the population was 1,644,561. At this
doubling rate, what could the
population be in 2048?
Write the correct answer.
1. If you invest $400, how much will it
be worth if it doubles in value twice?
4,096 cells
2. If an investment of $550 doubles in
value twice, how much will it be
worth?
$1,600
$2,200
3. If you invest $75, how much will it be
worth if it doubles in value 4 times?
4. If you invest $125, how much will it be
worth if it doubles in value 4 times?
$1,200
6. If an investment of $125 triples in
value 4 times, how much will it be
worth?
$2,025
$10,125
7. How much money did Jasmine save by the time she turned 18?
$300
8. How many times will her investment double from age 18 to age 60?
6 times
9. How much will Jasmine’s investment be worth when she turns 60?
$19,200
When Jake turned 13, he started saving $1.50 per week until he
turned 19. He then invested his total savings so that it tripled in
value every 12 years.
$468
10. How much money did Jake save by the time he turned 19?
3 times
11. How many times will his investment triple from age 19 to age 55?
17
Holt Mathematics
8. The number of cells of a certain type
of bacteria doubles every 45 minutes.
If you begin with a single cell, how
many cells could there be after
6 hours?
F 64
H 360
J 540
G 256
18
Why was the computer tired when it got home?
5
To find out, solve each problem. Write the letter on the line
above the correct answer at the bottom of the page. Each
answer must match exactly. Some letters will not be used.
5
3
34 T
49, base 7 K
103 B
81, base 9 I
26 64
D
52 25
181 3
4
Answer each question.
81
E
exponent
64 4 4 4
72
1,000
92
18
1. How do you read 53?
five to the third power
W
2. What does 53 mean?
five is a factor 3 times: 5 5 5
C
25, base 5 52
A
27, base 3 33
125
3. What is the value of 53?
4. Write about the difference between 53 and 35.
1
H
13 Sample answer: 53 means 5 5 5 125, and
V
122
35 means 3 3 3 3 3 243.
R
256, base 4 44
O
216, base 6 63
U
53 S
62
5. Write 32 using 2 as the repeated factor.
32 2 2 2 2 2
6. Write 32 using an exponent and a base of 2.
Holt Mathematics
LESSON
Exponents are an efficient way to express repeated multiplication.
64 7. In 2000, Wake County, North
Carolina, had a population of
610,284. This is about twice the
population in 1980. If the county
grows at the same rate every
20 years, what will its population be
in 2040?
A 915,426
C 1,830,852
B 1,220,568
D 2,441,136
Puzzles, Twisters & Teasers
1-2 Explore Your Power Base!
Reading Strategies
1-2 Reading and Understanding Symbols
Then write the product with a base
and an exponent.
6. The classroom is a square with a
side length of 13 feet and an area of
169 square feet. How can you write
the area in exponential form?
F 213
H 313
J 133
G 132
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
LESSON
You can describe some numbers as
the product of a repeated factor.
5. A theory states that the CPU clock
speed in a computer doubles every
18 months. If the clock speed was
33 MHz in 1991, how can you use
exponents to find out how fast the
clock speed is after doubling
3 times?
A 333
C 23 • 33
B 32 • 33
D 332
$12,636
12. How much will Jake’s investment be worth when he turns 55?
is read “3 to the fifth power.”
3
35 means 3 is a factor 5 times: 3 3 3 3 3.
35 243
is read “3 to the fifth power equals 243,”
or, “The value of 3 to the fifth power is 243.”
The base names the factor. The
exponent tells how many times to
base
repeat the base as a factor.
81 great-great-grandchildren
Choose the letter for the best answer.
When Jasmine turned 13, she started saving $5 per month until she
turned 18. She then invested her total savings so that it doubled in
value every 7 years.
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
4. Maria had triplets. Each of her
3 children had triplets. If the pattern
continued for 2 more generations,
how many great-great-grandchildren
would Maria have?
Prize B: $143,489.07
$2,000
5. If an investment of $75 triples in
value 3 times, how much will it be
worth?
13,156,488
3. A prizewinner can choose Prize A,
$2,000 per year for 15 years, or Prize
B, 3 cents the first year, with the
amount tripling each year through the
fifteenth year. Which prize is more
valuable? How much is it worth?
32 25
7. Write 216 using 6 as the repeated factor.
144
125
36
6 6 6 216
8. Write 216 using an exponent and a base of 6.
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
19
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
216 63
Holt Mathematics
B
E
C
A
U
S
E
I
T
H
A
D
92
81
52
33
125
36
81
64
72
1
33
25
A
H
A
R
D
D
R
I
V
E
33
1
33
44
25
25
44
64
144
81
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
108
20
Holt Mathematics
Holt Mathematics