Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers

Big Ideas Math Book 1st Grade Answer Key Chapter 9 Add Two-Digit Numbers

Add Two-Digit Numbers Vocabulary

Organize It

Review Words:
120 chart
column
ones
row
tens

Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 1
Answer:
Tens and ones.

Explanation:
The first row represents the tens and second row represents the ones
In tens row there are 3 lines 3 x 10 = 30.
In ones row there 7 boxes 7 x 1 = 7
so, total there are 37

Define It

Use the review words to complete the puzzle.

Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 2
Answer:
1) 120Chart
2) Column
3)Row

Explanation:
First figure shows the numbers from 1 to 120.
The vocabulary for the figure is 120 chart which is represented in the figure horizontally.
Second figure shows columns colored
The vocabulary for second figure is column
Third figure shows rows colored
The vocabulary for the third figure is row

Lesson 9.1 Add Tens and Ones

Explore and Grow

Show how you can use a model to solve.
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 3
32 + 7 = _________

Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 4
Answer:
32 + 7= 39 Three tens and 9 ones.
Explanation:
The first row represents the tens and second row represents the ones
In tens row there are 3 lines 3 x 10 = 30.
In ones row there 9 boxes 9 x 1 = 9
so, total there are 39

Show and Grow

Question 1.
25 + 12 = _________
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 5
Answer:
25 + 12 = 37 Three tens and 7 ones
Explanation:
The first row represents the tens and second row represents the ones
In tens row there are 2 lines 2 x 10 = 20.
In ones row there 5 boxes 5 x 1 = 5
so, total there are 25.
The first row represents the tens and second row represents the ones
In tens row there are 1 lines 1 x 10 = 10.
In ones row there 2 boxes 2 x 1 = 2
so, total there are 12
By adding both the numbers the answer is 37.

Question 2.
36 + 3 = __________
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 6
Answer:
36 +3= 39, three tens and 9 ones
Explanation:
The first row represents the tens and second row represents the ones
In tens row there are 3 lines 3 x 10 = 30.
In ones row there 6 boxes 6 x 1 = 6
so, total there are 36.
The first row represents the tens and second row represents the ones
In tens row there are 0 lines 0 x 10 = 0.
In ones row there 3 boxes 3 x 1 = 3
so, total there are 3
By adding both the numbers the answer is 39.

Question 3.
21 + 8 = __________
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 7
Answer:
21+ 8 = 29, 2 tens and 9 ones.
Explanation:
The first row represents the tens and second row represents the ones
In tens row there are 2 lines 2 x 10 = 20.
In ones row there 1 boxes 1 x 1 = 1
so, total there are 1.
The first row represents the tens and second row represents the ones
In tens row there are 0 lines 0 x 10 = 0.
In ones row there 8 boxes 8 x 1 = 8
so, total there are 8
By adding both the numbers the answer is 29.

Question 4.
22 + 24 = __________
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 8
Answer:
22 + 24 = 46, 4 tens and 6 ones
Explanation:
The first row represents the tens and second row represents the ones
In tens row there are 2 lines 2 x 10 = 20.
In ones row there 2 boxes 2 x 1 = 2
so, total there are 22.
The first row represents the tens and second row represents the ones
In tens row there are 2 lines 2 x 10 = 20.
In ones row there 4 boxes 4 x 1 = 4
so, total there are 24
By adding both the numbers the answer is 46.

Apply and Grow: Practice

Question 5.
34 + 4 = __________
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 9
Answer:
34 + 4 = 38, 3 tens and 8 ones.
Explanation:
The first row represents the tens and second row represents the ones
In tens row there are 3 lines 3 x 10 = 30.
In ones row there 4 boxes 4 x 1 = 4
so, total there are 34.
The first row represents the tens and second row represents the ones
In tens row there are 0 lines 0 x 10 = 0.
In ones row there 4 boxes 4 x 1 = 4
so, total there are 4
By adding both the numbers the answer is 38.

Question 6.
43 + 15 = __________
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 10

Answer:
43 + 15 = 58, 5 tens and 8 ones.

Explanation:
The first row represents the tens and second row represents the ones
In tens row there are 4 lines 4 x 10 = 40.
In ones row there 3 boxes 3 x 1 = 3
so, total there are 43.
The first row represents the tens and second row represents the ones
In tens row there are 1 lines 1 x 10 = 10.
In ones row there 5 boxes 5 x 1 = 5.
so, total there are 15
By adding both the numbers the answer is 58.

Question 7.
71 + 20 = __________
Answer:
71 + 20 = 91,
9 tens and 1 ones.

Explanation:
The number of choclates with rim is 71
The number of choclates with jim is 20
Total number of choclates is 91.

Question 8.
93 + 6 = __________
Answer:
93 + 6 = 99,
9 tens and 9 ones.

Explanation:
The number of choclates with rim is 93
The number of choclates with jim is 6
Total number of choclates is 99

Question 9.
55 + 23 = __________
Answer:
55 + 23 = 78, 7 tens and 8 ones.

Explanation:
The number of choclates with rim is 55
The number of choclates with jim is 23
Total number of choclates is 78.

Question 10.
62 + 32 = __________
Answer:
62 + 32 = 94, 9 tens and 4 ones.

Explanation:
The number of choclates with rim is 62
The number of choclates with jim is 32
Total number of choclates is 94.

Question 11.
MP Reasoning
Circle the number to complete the equation.
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 11
Answer:
41 + 5 = 46,
Circled the number 5.

Think and Grow: Modeling Real Life

You watch television for 24 minutes in the morning and 32 minutes at night. How many minutes do you spend watching television in all?
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 12
Addition equation:

Model:

___________ minutes
Answer: 56

Explanation:
Models: television,
24 minutes in the morning and 32 minutes in the night
24 + 32 = 56.

Show and Grow

Question 12.
You do 42 jumping jacks in the morning and 46 at night. How many jumping jacks do you do in all?
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 13
Addition equation:

Model:

___________ jumping jacks
Answer: 88

Explanation:
Models : Jumping jacks,
42 jumping jacks in the morning and 46 in the night
42 + 46 = 88. 88 Jumping jacks

Add Tens and Ones Practice 9.1

Question 1.
42 + 7 = _________
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 14
Answer:
42 + 7 = 49, 4 tens and 9 ones.

Explanation:
The first row represents the tens and second row represents the ones
In tens row there are 4 lines 4 x 10 = 40.
In ones row there 2 boxes 2 x 1 = 2.
so, total there are 42.
The first row represents the tens and second row represents the ones
In tens row there are 0 lines 0 x 10 = 0.
In ones row there 7 boxes 7 x 1 = 7
so, total there are 7
By adding both the numbers the answer is 49.

Question 2.
61 + 35 = __________
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 15
Answer:
61 + 35 = 96, 9 tens and 6 ones.

Explanation:
The first row represents the tens and second row represents the ones
In tens row there are 6 lines 6 x 10 = 60.
In ones row there 1 boxes 1 x 1 = 1
so, total there are 61.
The first row represents the tens and second row represents the ones
In tens row there are 3 lines 3 x 10 = 30.
In ones row there 5 boxes 5 x 1 = 5
so, total there are 35
By adding both the numbers the answer is 96.

Question 3.
74 + 11 = __________
Answer:
74 + 11 = 85, 8 tens and 5 ones.

Explanation:
The number of choclates with rim is 74
The number of choclates with jim is 11
Total number of choclates is 85.

Question 4.
86 + 2 = ___________
Answer:
86 + 2 = 88, 8 tens and 8 ones.

Explanation:
The number of choclates with rim is 86
The number of choclates with jim is 2
Total number of choclates is 88.

Question 5.
MP Reasoning
Circle the number to complete the equation.
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 16
Answer:
22 + 70 =  92, circled the 70 to complete the number.

Question 6.

Modeling Real Life
You eat 33 grapes. Your friend eats 23 grapes. How many grapes do you and your friend eat in all?
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 17

___________ grapes
Answer: 55

Explanation:
Me ate 33 and my friend ate 23 in all
33 + 23 = 55.
We bote ate 55 in all.

Review & Refresh

Question 7.
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 18
__________ tens and _________ ones is _________ .
Answer:
8 tens and 2 ones is 82

Explanation:
The first row represents the tens and second row represents the ones
In tens row there are 8 lines 8 x 10 = 80.
In ones row there 2 boxes 2 x 1 = 2
so, total there are 82.

Question 8.
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 19
__________ tens and _________ ones is _________ .
Answer:
4 tens and 6 ones is 46

Explanation:
The first row represents the tens and second row represents the ones
In tens row there are 4 lines 4 x 10 = 40.
In ones row there 6 boxes 6 x 1 = 6
so, total there are 46.

Lesson 9.2 Add Tens and Ones Using a Number Line

Explore and Grow

Color to show how you can use the hundred chart to find the sum.

23 + 34 = ___________

Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 20
Answer:
23 + 34 = 57,
5 tens and 7 ones.

Explanation:
In the below figure 120 chart is shown in that 23 and 34 are colored
that two numbers are added
to get the total sum.

Show and Grow

Question 1.
22 + 7 = __________
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 21
Answer: 29

Explanation:
22 + 7 = 29,
the addition is represented on number line

Question 2.
35 + 41 = __________
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 22
Answer:
35 + 41 = 76.

Explanation:
35 + 41 is represented on the number line.

Apply and Grow: practice

Question 3.
53 + 40 = _________
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 23
Answer:
53 + 40 = 93.

Question 4.
82 + 12 = __________
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 24
Answer: 82 + 12 = 94.

Question 5.
48 + 31 = ___________
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 24
Answer: 48 + 31 = 79.
From the above equation 48 is marked and from that point
3 points with 10 are taken and 1 with one is taken
48 + 31 = 79

Question 6.
MP Structure
Write an equation that matches the number line.
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 25
Answer: 37 + 23 = 60

Explanation:
From the point 37 to 60
2 points with 10 are taken and 3 points with 1 are taken
so, the total equation is 37 + 23 = 60.

Think and Grow: Modeling Real Life

The home team scores 37 points. The visiting team scores 22 more. How many points does the visiting team score?
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 26
Addition equation:

Model:
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 27

__________ points
Answer: 37 + 22 = 59

Explanation:
A point on the number line is taken as 37
From there 2 poins with 10 that is 20
From there 2 more points with 2 are taken
total it makes 22

Show and Grow

Question 7.
Your friend scores 63 points. You score 25 more than your friend. How many points do you score?
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 28
Addition equation:

Model:
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 27

__________ points
Answer: 63 + 25 = 88
Explanation:
A point on the number line is taken as 63
From there 2 poins with 10 that is 20
From there 5 more points with 5 are taken
total it makes 88.

Add Tens and Ones Using a Number Line Practice 9.2

Question 1.
13 + 60 = __________
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 29
Answer: 73

Question 2.
81 + 8 = _____________
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 30
Answer: 89

Question 3.
56 + 42 = ____________
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 30
Answer: 98

Question 4.
MP Structure
Write an equation that matches the number line.
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 31
Answer: 17 + 41= 58

Question 5.
Modeling Real Life
There are 36 black keys on a piano. There are 16 more white keys than black keys. How many white keys are there?
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 32
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 33

____________ white keys
Answer: 52 white keys

Review & Refresh

Question 6.
3 + 7 + 4 = ___________
Answer: 14

Question 7.
4 + 5 + 6 = ___________
Answer: 15

Lesson 9.3 Make a 10 to Add

Explore and Grow

How can you use the model to solve?

38 + 6 = ___________

Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 34
Answer:
38 + 6 = 44

Explanation:
The first row represents the tens and second row represents the ones
In tens row there are 3 lines 3 x 10 = 30.
In ones row there 8 boxes 8 x 1 = 8
so, total there are 38.
The first row represents the tens and second row represents the ones
In tens row there are 0 lines 0 x 10 = 0.
In ones row there 6 boxes 6 x 1 = 6
so, total there are 6
By adding both the numbers the answer is 44.
Count one numbers from both the sides 8 + 6 = 14
It has 10 in it

Show and Grow

Question 1.
41 + 7 = ___________
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 35
Make a 10?           Yes         No
Answer: No

Explanation:
By adding ones place from both the sides
1 + 7 = 8
So, the answer is no

Question 2.
56 + 8 = ___________
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 36
Make a 10?           Yes         No
Answer: Yes

Explanation:
By adding ones place from both the sides
6 + 8 = 14
So, there is 10 in it.

Apply and Grow: Practice

Question 3.
72 + 4 = _________
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 37
Make a 10?           Yes         No
Answer: No

Explanation:
By adding ones place from both the sides
2 + 4 = 6
So, There is no 10 in it.

Question 4.
63 + 9 = ___________
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 38
Make a 10?           Yes         No
Answer: Yes

Explanation:
By adding ones place from both the sides
3  + 9 = 11
So, there is 10 in it.

Question 5.
14 + 6 = __________
Make a 10?           Yes         No
Answer: Yes

Explanation:
By adding ones place from both the sides
4 + 6 = 10
so, there is 10 in it.

Question 6.
27 + 5 = __________
Make a 10?           Yes         No
Answer: Yes

Explanation:
By adding ones place from both the sides
7 + 5 = 12
So, there is 10 in it.

Question 7.
46 + 7 = ___________
Make a 10?           Yes         No
Answer: Yes

Explanation:
By adding ones place from both the sides
6 + 7 = 13
So, there is 10 in it

Question 8.
81 + 8 = ___________
Make a 10?           Yes         No
Answer: No

Explanation:
By adding ones place from both the sides
1 + 8 = 9
so, there is 10 in it.

MP Logic
Complete.
Question 9.
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 39

Answer: 62

Explanation:
56 + 6 = 62
56 + 4 makes 60 and 4 + 2 = 6
6 is divided as 4 + 2
60 + 2

Question 10.
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 40
Answer: 48


Explanation:
39 + 9 = 48
39 + 1 = 40, 9 is divided to 1 and 8.

Think and Grow: Modeling Real Life

You put 17 puzzle pieces together. There are 7 left. How many puzzle pieces are there in all?
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 41
Addition equation:

Model:

Make a 10?           Yes         No

___________ Puzzle pieces
Answer: Yes.

Explanation:
17 puzzle pieces are together
7 added to it
17 + 7 = 24
The ones place of both sides are added 7 + 7 = 14
so, there is ten in it.

Show and Grow

Question 11.
You color 46 states. There are 4 left. How many states are there in all?
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 42
Addition equation:

Model:

Make a 10?           Yes         No

___________ States
Answer: 50

Explanation:
Colored states are 46
uncolored states are 4
Total states are 46 + 4 = 50
6 + 4 = 10
Both the sides ones places are added

Make a 10 to Add Practice 9.3

Question 1.
66 + 5 = __________
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 43
Make a 10?           Yes         No
Answer: yes

Explanation:
Number of lines which represents 10 is 6 that in tens place
in ones place both the sides 6 + 5 = 11
so, there is 10 in it

Question 2.
74 + 3 = ____________
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 44
Make a 10?           Yes         No
Answer: No

Explanation:
Number of lines which represents 10 is 7 that in tens place
in ones place both the sides 4 + 3 = 7.
so, there is no 10 in it.

Question 3.
28 + 8 _____________
Make a 10?           Yes         No
Answer: Yes

Explanation:
2 represents tens place 2 x 10 = 20
In ones place from both the sides 8 + 8 = 16
so, There is ten in it.

Question 4.
52 + 9 = ______________
Make a 10?           Yes         No
Answer: Yes

Explanation:
5 represents tens place 5 x 10 = 50
In ones place from both the sides 2 + 9 = 11
so, There is ten in it.
52 + 9 = 61.

Question 5.
26 + 7 = ____________
Make a 10?           Yes         No
Answer: yes

Explanation:
2 represents tens place 2 x 10 = 20
In ones place from both the sides 6 + 7 = 13
so, There is ten in it.
26 + 7 = 33.

Question 6.
41 + 6 = ____________
Make a 10?           Yes         No
Answer: No

Explanation:
4 represents tens place 4 x 10 = 40
In ones place from both the sides 1 + 6 = 7
so, There is no ten in it.
41 + 6 = 47.

MP Logic
Complete.
Question 7.
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 45
Answer: 41


Explanation:
37 + 4 = 41
4 is divided to 3 and 1
37 + 3 = 40
40 plus 1 is 41

Question 8.
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 46
Answer: 54

Explanation:
48 + 6 = 54
6 is divided in to 2 and 4
48 + 2 = 50 So, there is ten in it
50 + 4 = 54

Question 9.
Modeling Real Life
A snake lays 24 eggs. Another snake lays 9 eggs. How many eggs are there in all?
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 47
Answer:
33 eggs

Explanation:
A snake lays 24 eggs
another snake lays 9
there are 33 eggs in all.

Review & Refresh

Question 10.
Color the shapes that have 4 vertices.
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 48
Answer:  Square and rectangle

Explanation:
For square there are 4 vertices and
and for rectangle there are 4 vertices.
vertices are Nothing but corners or joining of the two lines.

Lesson 9.4 Add Two-Digit Numbers

Explore and Grow

Show how you can use a model to solve.
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 49

43 + 28 = _________
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 50
Answer: 43 + 28 = 61

Explanation:
4 tens and 3 ones
2 tens and 8 ones
The figure shows lines represents tens and
circls represent ones

Show and Grow

Question 1.
39 + 45 = ?
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 51
___________ tens __________ ones
Answer: 7 tens and 14 ones

Explanation:
The figure shows 39 represents 3 tens and 9 ones
and 4 tens 5 ones
3 + 4 = 7 and 9 + 5 = 14.

Apply and Grow: Practice

Question 2.
19 + 35 = ?
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 52
Answer: 1 + 3 = 4 and 9 + 5 = 14

Explanation:
First figure shows 1 tens and 9 ones
3 tens and 5 ones
The second figure shows 1 + 3 = 4
and 9 + 5 = 14

Question 3.
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 53
Answer: 60
Explanation:
43 + 17 = 60
In the 4 and 3 are in tens place and 3 and 7 are in ones place
My friend has 43 choclates and me has 17 more of it.
Total choclates is 60.

Question 4.
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 54
Answer: 81

Explanation:
67 + 41 = 81
my friend jim has 67 lollipops
and rim has 41 lollipops
in total jim and rim has 81 lollipops.

Question 5.
YOU BE THE TEACHER
Is the sum correct? Explain.
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 55
Answer: 76
Explanation:

58 + 28 = 76
The line represents 10 and circles represents 1
5 tens and 8 ones
2 tens and 8 ones
by adding 8 from the both places we get 16 and there is 10 in it.

Think and Grow: Modeling Real Life

You earn a sticker for every 10 pages you read. You read 34 pages one week and 37 the next. How many stickers do you earn?
Addition problem:
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 56
Model:
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 57
Write the missing numbers:
_________ tens _________ one
__________ stickers
Answer: 71

Explanation:
I earn a sticker for every 10 pages
first I read 34 pages and then 37 pages
34 + 37 = 71
so, total 71 pages for every 10 pages 1 sticker 7 stickers

Show and Grow

Question 6.
You earn a coin for every lo cans you recycle. You recycle 18 cans one week and 25 the next. How many coins do you earn?
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 58
Addition problem:
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 59
Model:
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 60
Write the missing numbers:
_________ tens _________ one
__________ coins
Answer:  4 tens and 3 ones 4 coins
Explanation:
If I recycle 10 cans I get 1 coin
in first week i recycled 18 cans and in next week 25 cans
18 + 25 = 43.

Add Two-Digit Numbers Practice 9.4

Question 1.
57 + 15 = ?
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 61
Answer: 57 + 15 = 72

Explanation:
In 57 5 tens and 7 ones
in 15 1 tens and 5 ones
If we add both we get 7 tens and 2 ones.

Question 2.
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 62
Answer: 76

Explanation:
In 40 4 tens and 0 ones
in 36 3 tens and 6 ones
if we add both we get 7 tens and 6 ones.

Question 3.
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 63
Answer: 81
Explanation:
In 29 2 tens and 9 ones
in 52 5 tens and  2 ones
If we add both 29 and 52 is 81
8 tens and 1 ones.

Question 4.
DIG DEEPER!
Do you need to use the make a 10 strategy to find each sum?
28 + 34 = ?      Yes      No
56 + 15 = ?      Yes      No
42 + 21 = ?      Yes      No
68 + 11 = ?      Yes      No
Answer:
28 + 34 = 62      Yes
56 + 15 = 71    Yes
42 + 21 = 63      No
68 + 11 = 79     No
Explanation:
In first sum 28 + 34
if we take 8 and 4 and add we get 12 taken from ones place
we get 10 in it.
In second sum 56 + 15
if we take 6 and 5 and add we get 11 taken from ones place
we get 10 in it.
In third sum 42 + 21
if we take 2 and 1 and add we get 3 taken from ones place
we didn’t get 10 in it
In fourth sum 68 + 11
if we take 8 and 1 and add we get 9 taken from ones place
we didn’t get 10 in it.

Question 5.
You need a box for every 10 muffins you make. You make 33 blueberry muffins and 47 banana muffins. How many boxes do you need?
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 64

__________ boxes
Answer: 8 boxes
Explanation:
We need a box for 10 muffins that we make
We made 33 blueberry muffins
and 47 banana muffins
if we add we get 33 + 47 = 80
so, I get 8 boxes.

Review & Refresh

Question 6.
Is the equation true or false?
Big Ideas Math Answer Key Grade 1 Chapter 9 Add Two-Digit Numbers 65
Answer: 15 = 16 false

Explanation:
6+ 9 = 15 and 17 – 1= 16
15 is not equal to 16

Lesson 9.5 Practice Addition Strategies

Explore and Grow

Show two ways you can find the sum.

23 + 39 = __________

23 + 39 = __________

Answer:  23 + 39 = 62
Explanation: one method

second method

Show and Grow

Question 1.
47 + 24 = ________
Answer: 72

Explanation:
4 tens and 7 ones
2 tens and 4 ones
tens represents the lines and ones represents the circles

Question 2.
38 + 43 = ________
Answer: 81

Explanation:
3 tens and 8 ones
4 tens and 3 ones
tens represents the lines and ones represents circles

Apply and Grow: Practice

Question 3.
22 + 18 = ________
Answer: 40

Explanation:
2 tens and 2 ones
1 tens and 8 ones
tens represents the lines and ones represents the circles

Question 4.
57 + 34 = __________
Answer: 91

Explanation:
5 tens and 7 ones
3 tens and 4 ones
lines represents the tens and circles represents the ones

Question 5.
73 + 19 = __________
Answer: 92

Explanation:
lines represents the tens and circles represents the ones
7 ten and 3 ones
1 tens and 9 ones

Question 6.
81 + 11 = __________
Answer: 92

Explanation:
the lines represents tens and the circles represents ones
8 tens and 1 ones
1 tens and 1 ones
If we add both we get
92

Question 7.
YOU BE THE TEACHER
Is the sum correct? Explain.
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 66
Answer: No

Explanation:
no the sum is not correct.
But figure shown is correct
17 + 26 = 43

Think and Grow: Modeling Real Life

You hove 48 songs. Your friend has 27 more than you. How many songs does your friend have?
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 67
Addition equation:

Model:

____________ songs
Answer: 75 songs

Explanation:
Model : songs
I have 48 songs
and my friend had 27 more than me
Total songs that my friend had is 48 + 27 = 75 songs

Show and Grow

Question 8.
Your friend sells 56 candles. You sell 35 more than your friend. How many candles do you sell?
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 68
Addition equation:

Model:

____________ candles
Answer: 91 candles

Explanation:
Models: candles
My friend has 56 candles
and me has 35 more than my friend
so, I had 91 candles with me

Practice Addition Strategies Practice 9.5

Question 1.
62 + 29 = _______
Answer: 99

Explanation:
6 tens and 2 ones
2 tens and 9 ones
by adding both the numbers i get is 99

Question 2.
84 + 8 = ________
Answer: 92

Explanation:
8 tens and 4 ones
0 tens and 8 ones
by adding both the numbers i get is 92

Question 3.
75 + 17 = ________
Answer: 92

Explanation:
7 tens and 5 ones
1 tens and 7 ones
by adding both the numbers i get is 92

Question 4.
YOU BE THE TEACHER
Is the sum correct? Explain.
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 69
Answer:

Question 5.
Modeling Real Life You collect 12 leaves. Your friend collects 26 more than you. How many leaves does your friend collect?
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 70

____________ leaves
Answer: 38 leaves

Explanation:
I collect 12 leaves and my friend collect 26 more than me
total leaves my friend had is
12 + 26 = 38 leaves.

Review & Refresh

Question 6.
Circle the measurable attributes of the table.
Big Ideas Math Answers 1st Grade 1 Chapter 9 Add Two-Digit Numbers 71
Answer: length or height.

Explanation:
For table length or height is the measuring attribute
cubes represents to measure the length and height.

Lesson 9.6 Problem Solving: Addition

Explore and Grow

Model the story.

Newton has 15 dog bones. Descartes gives him 8 more. How many dog bones does Newton have now?

Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 72
Answer: 23 bones

Explanation:
Newton has 15 bones and Descartes gave him 8 more
The total bones newton had is 23 bones.

Show and Grow

Question 1.
You have 49 toy soldiers. You buy some more. Now you have 84. How many toy soldiers did you buy?
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 73
Circle what you know:

Underline what you need to find.

Solve:

_____________ toy soldiers
Answer: 35 toy soldiers

Explanation:
I have 49 toy soldiers
If i buy 35 more
Then i will have 84 in total.

Apply and Grow: Practice

Question 2.
You have 55 pounds of dog food and some cat food. You have 63 pounds of pet food in all. How many pounds of cat food do you have?
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 74
Circle what you know.

Underline what you need to find.

Solve:

___________ pounds
Answer:  8 pounds

Explanation:
I have 55 pound of dog food
If i had 8 pounds of cat food
In total the pet food had is 63 pounds

Question 3.
A teacher has 34 erasers. There are 46 fewer erasers than pencils. How many pencils are there?

____________ pencils
Answer:

Question 4.
DIG DEEPER!
You have 25 toys. Your friend has more than you. There are more than 60 toys in all. How many toys can your friend have?
29       33       24      38
Answer: 35 toys

Explanation:
I have 25 toys
and if had 35 then the total toys will be 60
according to the given options it might be less than 35
29, 33 or 24

Think and Grow: Modeling Real Life

You need 60 invitations. You have 36 and buy 36 more. Do you have enough invitations?
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 75
Circle what you know.

Underline what you need to find.

Solve:

Compare: ___________ ○ 60        Yes          No
Answer: yes

Explanation:
66 > 60
I had 6 more invitations
Yes they have enough invitations.

Show and Grow

Question 5.
You need 84 bottles of water. You have 48 and buy 32 more. Do you have enough bottles of water?
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 76
Circle what you know.

Underline what you need to find.

Solve:

Compare: ___________ ○ 84        Yes          No
Answer:  No

Explanation:
The waterbottles i had 80
The waterbottles needed is 84
80 < 84
so, there are no enough waterbottles

Problem Solving: Addition Practice 9.6

Question 1.
You have 31 stuffed animals. You and your friend have 60 stuffed animals in all. How many stuffed animals does your friend have?

______________ stuffed animals
Answer:  29

Explanation:
31 + 29 = 60,
There are 29 stuffed animals with my friend.

Question 2.
A store has 56 shirts. There are 28 fewer shirts than pairs of pants. How many pairs of pants are there?

______________ Pairs of pants
Answer: 28

Explanation:
Total shirts is 56 and 56 – 28 = 28,
The pairs of paints are 28.
28 + 28 = 56.

Question 3.
YOU BE THE TEACHER
You have 25 movies. You have 18 more video games than movies. Your friend says you have (43 movies and video games in all. Is your friend correct? Explain.

___________________________________________________

___________________________________________________
Answer: 43:

Explanation
Me having 25 movies and 18 videogames 25 + 18 = 43,
Yes my friend is correct I have 43 movies and  videogames in all.

Question 4.
Modeling Real Life
Newton needs 9o chairs for a party. He has 51. He rents 3 more. Does Newton have enough chairs?

Circle:         Yes          No
Answer: No,

Explanation:
Newton doesn’t have enough chairs.
He needed is 90 he has 51 + 3 = 54.

Review & Refresh

Circle the longer object.

Question 5.
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 77
Answer:
The scissor is longer than the brick
circled the scissor

Question 6.
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 78
Answer:
The first pencil is longer than the second pencil
First pencil is circled

Add Two-Digit Numbers Performance Task

Question 1.
You play a game. Each red ball you collect is worth 10 points. Each yellow ball you collect is worth 1 point.
Big Ideas Math Answers Grade 1 Chapter 9 Add Two-Digit Numbers 79

a. You collect 3 red balls and 13 yellow balls. How many points do you have?

___________ points
Answer: 30

Explanation
Red ball = 10
yellow = 1.
I have collected 3 red and 13 yellow,
3 × 10 = 30

39 + 13 = 52. Total points are 52.

b. Your teammates score 38 points and 24 points. How many points do your teammates have in all?

___________ points
Answer:
38 + 24 = 62,
62 points our teammates have in all.

c. Your learn wants to have 100 points. Does your team reach its goal?

Yes No
Answer: No,
we didn’t reach the goal.

d. Why do you think a red ball is worth more points?
Answer:
Because it is small in size and easy to handle to kids by seeing in figure.

Add Two-Digit Numbers Change Practice

Add Tens and Ones Homework & Practice 9.1

Question 1.
56 + 3 = _________
Big Ideas Math Solutions Grade 1 Chapter 9 Add Two-Digit Numbers 80
Answer:
53 + 3 = 56,
5 tens and 6 ones.

Question 2.
22 + 54 = __________
Big Ideas Math Solutions Grade 1 Chapter 9 Add Two-Digit Numbers 81
Answer:
24 + 54 = 78,
7 tens and 8 ones.

Add Tens and Ones Using a Number Line Homework & Practice 9.2

Question 3.
62 + 25 = ___________
Big Ideas Math Solutions Grade 1 Chapter 9 Add Two-Digit Numbers 82
Answer: 62 + 25 = 87

Explanation:
6 tens and 2 ones
2 tens and 5 ones
by adding both we get 87

Question 4.
38 + 51 = ___________
Big Ideas Math Solutions Grade 1 Chapter 9 Add Two-Digit Numbers 82
Answer: 38 + 51 = 89

Explanation:
3 tens and 8 ones
5 tens and 1 ones
by adding both we get 89.

Question 5.
MP Structure
Write an equation that matches the number line.
Big Ideas Math Solutions Grade 1 Chapter 9 Add Two-Digit Numbers 83
Answer: 16 + 52 = 68

Make a 10 to Add Homework & Practice 9.3

Question 6.
42 + 6 = ___________
Big Ideas Math Solutions Grade 1 Chapter 9 Add Two-Digit Numbers 84
Make a 10?       Yes           No
Answer: No

Explanation:
lines represents the tens and circles represents the ones
4 tens and 2 ones
0 tens and 6 ones
By adding ones place from both the sides 2 + 6 = 8
so there is no 10 in it.

Question 7.
27 + 7 = ___________
Big Ideas Math Solutions Grade 1 Chapter 9 Add Two-Digit Numbers 85
Make a 10?       Yes           No
Answer: yes

Explanation:
lines represents the tens and circles represents the ones
2 tens and 7 ones
0 tens and 7 ones
By adding ones place from both the sides 7 + 7 = 14
so there is 10 in it

MP Logic
Complete.
Question 8.
Big Ideas Math Solutions Grade 1 Chapter 9 Add Two-Digit Numbers 86
Answer:
34 + 7 = 41.

Question 9.
Big Ideas Math Solutions Grade 1 Chapter 9 Add Two-Digit Numbers 87
Answer:
59 + 8 = 67

Add Two-Digit Numbers Homework & Practice 9.4

Make quick sketches to find the sum.

Question 10.
Big Ideas Math Solutions Grade 1 Chapter 9 Add Two-Digit Numbers 88
Answer:
28 + 33 = 61, 6 tens and 1 ones.

Question 11.
Big Ideas Math Solutions Grade 1 Chapter 9 Add Two-Digit Numbers 89

____________ tens ___________ one
Answer:
49 + 24 =73, 7 tens and 3 ones.

Question 12.
Modeling Real Life
Your club earns a badge for every 10 trees planted. Your club plants 25 trees in the fall and 25 in the spring. How many badges does your club earn?
Big Ideas Math Solutions Grade 1 Chapter 9 Add Two-Digit Numbers 90

_______________ badges
Answer:
One badge for 10, 25 in spring and 25 in fall.
Total trees planted is 25 + 25 = 50.
So, 5 badges.

Practice Addition Strategies Homework & Practice 9.5

Question 13.
19 + 43 = __________
Answer: 19 + 43 = 62, 6 tens and 2 ones.

Question 14.
66 + 28 = __________
Answer: 66 + 28 = 94, 9 tens and 4 ones.

Problem Solving: Addition Homework & Practice 9.6

Question 15.
Your friend has 5 marbles. You have 23 more than your friend. How many marbles do you have?
Big Ideas Math Solutions Grade 1 Chapter 9 Add Two-Digit Numbers 91

_______________ marbles
Answer:  28 marbles

Explanation
My friend has 5 and me having 23 more
than my friend 23 + 5 = 28.

Question 16.
Modeling Real Life
You need 50 party hats. You have 24. You buy 16 more. Do you have enough party hats?
Big Ideas Math Solutions Grade 1 Chapter 9 Add Two-Digit Numbers 92

Yes           No
Answer: No

Explanation:
Me having 24 caps and bought 16 more
24 + 16 = 40,
No I don’t have enough caps.

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