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Name
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Date
LESSON
Class
Practice A
5-8 Adding and Subtracting Mixed Numbers
Estimate each sum or difference to the nearest whole number.
1
1
1. 2!5! ! 1!4!
1
1
4
2. 3!6! ! 1!5!
3
2
4. 1!2! ! 2!4!
1
1
3. 4!2! " 2!8!
5
1
5. 2!3! " 1!6!
1
6. 1!7! " 1!8!
Find each sum or difference. Write each answer in simplest form.
1
1
2
1
1
1
7. 1!2! ! 3!4!
10. 3!6! " 1!3!
2
1
1
1
16. 2!1!
! 1!8!
2
2
1
11. 10!3! " 9!4!
13. 8!2! ! 2!3!
7
3
!
8. 10!5! " 8!
10
1
2
1
! ! 1!!
12. 4!
15
5
1
1
15. 7!8! ! 1!6!
1
1
17. 4!6! " 1!9!
1
1
18. 3!7! ! 3!3!
1
20. 5!5! ! 1!2!
1
1
1
21. 2!3! ! 2!5!
23. Bonita planted an oak tree and an
elm tree in her backyard. Three years
1
later, the oak tree was 5!6! feet tall,
1
and the elm tree was 7!2! feet tall.
How much taller was the elm tree?
22. Jack babysat for 4!4! hours on Friday
2
night. He babysat for 3!3! hours on
Saturday night. How many hours did
he babysit in all?
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
5
14. 12!2! " 10!8!
2
19. 1!3! " 1!2!
1
1
9. 3!4! ! 2!6!
72
Holt Middle School Math Course 1
Exploration Recording Sheet
5-8 Adding and Subtracting Mixed Numbers
Puzzles, Twisters & Teasers
5-7 The Truth of the Matter
LESSON
LESSON
Decide whether each statement is true or false. Circle
your answer.
The graph shows typical rainfall levels for a city in the Southwest for
the first 5 months of the year. What is the approximate total rainfall
from January through May?
Use the letters of your true answers and rearrange them
to answer the question.
3
Rainfall (in.)
M true
E false
!
7
3
1
1
10
!! ! !! " !! ! !! " !!
21
21
3
7
21
2. one-fourth plus one-ninth is greater than one-third
C true
!
24
3
1. one-third plus one-seventh is greater than one-half
P false
14
2
5
1
1
1
9
4
13
!! ! !! " !! ! !! " !!
4
9
36
36
36
Jan
3. four-fifths minus one-third is less than one-half
D true
!
12
5
Feb
Mar
Apr
5
7
4
1
12
!! # !! " !! # !! " !!
15
15
5
3
15
Estimated
A true
The total rainfall is about 7 inches.
4. three-fourths minus three tenths equals one-half
S false
!
3
3
15
6
9
!! # !! " !! # !! " !!
4
10
20
20
20
1
7
9
3
14
23
!! ! !! " !! ! !! " !!
12
24
8
24
24
7
2. 1!2! ! 9!8! # 2!4!
18 ! 19 " 37
4. 4!8! # 1!1!
! 3!4!
0
1
3
1
1
3
1
2!9#2"9
4#1!3"6
5. Discuss the estimation strategies you used.
Possible answer: Determined which whole number the fraction
was closest to then added or subtracted.
What must you find in order to add or subtract unlike fractions?
C
1
14 # 10 " 4
Think and Discuss
B false
3
9
3
6
3
1
!! # !! " !! # !! " !! " !!
12
12
12
12
4
2
L
27
3. 17!8! ! 19!1!
0
6. three-fourths minus three-twelfths equals one-half
The
3 ! 2 ! 1 ! 1 ! 0 " 7 in.
!
1. 13!2! # 9!
32
T false
!
L true
!
May
Estimate each sum or difference.
5. seven-twelfths plus three-eighths is greater than one
J true
3
8
3
4
2
3
3
2!4! ! 1!5! ! 1!5! ! !4! ! !8!
Actual
N false
3
4
A mixed number contains
a whole number and a
fraction. To estimate with
mixed numbers, round each
mixed number to the nearest
whole number.
D
6. Describe a real-world situation in which mixed numbers are
added or subtracted.
Possible answer: Adding snowfall amounts, measuring lengths
of wood.
69
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
Holt Middle School Math Course 1
Practice A
5-8 Adding and Subtracting Mixed Numbers
LESSON
Estimate each sum or difference to the nearest whole number.
1
1
1
4
3
1
Find each sum or difference. Write each answer in simplest form.
1
2. 3!6! ! 1!5!
1
3
2
5
1
1
5
1
1
3
4!4!
1
1
5
1
1
13. 8!2! ! 2!3!
1
1
14. 12!2! # 10!8!
5
1
1
! ! 1!!
16. 2!
12
8
1
1
3!1!
8
6!2!
1
1
17
1
2
19. 1!3! # 1!2!
1
1
21. 2!3! ! 2!5!
6!1!
0
4!1!
5
1
7!11! hours
2
2
3
4
1
15. 3!5! # 2!2!
1
1
!!
5
3
2
19
50!3!
5
1!1!
0
1
1
!
17. 4!5! ! 2!
10
1
18. 32!2! ! 5!3!
9
6!1!
0
5
37!6!
1
8
Donald buy in all?
9
5!2!
pounds
0
4
2!1! feet
12
1
12. 25!7! ! 25!5!
19. Donald is making a party mix. He bought 2!4! pounds of pecans
1
and 3!5! pounds of walnuts. How many pounds of nuts did
23. Bonita planted an oak tree and an
elm tree in her backyard. Three years
1
later, the oak tree was 5!6! feet tall,
1
and the elm tree was 7!2! feet tall.
How much taller was the elm tree?
22. Jack babysat for 4!4! hours on Friday
2
night. He babysat for 3!3! hours on
Saturday night. How many hours did
he babysit in all?
3
!
14. 1!5! # 1!
10
9
3!2!
0
1
20. 5!5! ! 1!2!
1
!
16. 6!4! # 3!
10
10
9
1
!!
6
3
13
22!2!
4
7
9!1!
0
11
1
18. 3!7! ! 3!3!
1
3
9. 21!6! ! 1!8!
! ! 4!!
11. 5!
15
10
4!1!
5
8!2!
4
17. 4!6! # 1!9!
3!2!
4
2
7
2!8!
6
3
13. 3!5! ! 1!3!
1
1
15. 7!8! ! 1!6!
3
10!6!
7
5!3!
1
17!3!
5
4!4!
4
5
1!2!
4
1
1
6. 12!4! ! 5!1!
2
7
3
!
8. 5!4! # 1!
11
1
7
1
1!1!
2
2
1
5
! # 14!!
10. 15!
12
8
2
1
! ! 1!!
12. 4!
15
5
2
1
11. 10!3! # 9!4!
5
18!2!
1
1
15!6!
1
6!1!
2
2
10!9!
4
7. 29!3! # 14!6!
5
1
3. 7!3! ! 3!9!
5. 32!7! # 14!3!
7
9. 3!4! ! 2!6!
1
2!2!
2
1
10. 3!6! # 1!3!
2
1
3
!
8. 10!5! # 8!
10
1
5!1!
2
0
1
1
3!1!
5
4. 22!6! # 17!4!
Find each sum or difference. Write each answer in simplest form.
7. 1!2! ! 3!4!
2
2. 11!5! # 8!3!
5
9!8!
6. 1!7! # 1!8!
1
1
1. 4!8! ! 5!4!
1
2!2!
5. 2!3! # 1!6!
1
4!2!
3
3. 4!2! # 2!8!
5
4. 1!2! ! 2!4!
Holt Middle School Math Course 1
Practice B
5-8 Adding and Subtracting Mixed Numbers
LESSON
1. 2!5! ! 1!4!
71
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
20. Mrs. Watson’s cookie recipe calls for 3!7! cups of sugar.
2
Mr. Clark’s cookie recipe calls for 4!3! cups of sugar.
How much more sugar does Mr. Clark’s recipe use?
5
2
1!2!
cups more
1
1
! lb. Naomi’s cat weighs 11!! lb. Can
21. Tasha’s cat weighs 15!
12
3
they bring both of their cats to the vet in a carrier that can hold
up to 27 pounds? Explain.
Yes; because the cats’ combined weight is 26!3! pounds,
3
4
which is less the 27 pounds
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
72
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
Holt Middle School Math Course 1
Copyright © by Holt, Rinehart and Winston.
All rights reserved.
124
73
Holt Middle School Math Course 1
Holt Middle School Math Course 1