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Portions of this instructional unit were adapted from the Arizona Academic Content Standards, Ohio Model Curriculum for Mathematics and North Carolina Common Core Mathematics Unpacked Content.
CCGPS Math Instructional Unit
Third Grade
Unit 1
Place value: Addition and Subtraction
Suggested Pacing:
25 days
Standards
Students are expected to:
1. Make sense of problems and persevere in solving them.
In third grade, students know that doing mathematics involves solving problems and discussing
how they solved them. Students explain to themselves the meaning of a problem and look for
ways to solve it. Third graders may use concrete objects or pictures to help them conceptualize
and solve problems. They may check their thinking by asking themselves, “Does this make
sense?” They listen to the strategies of others and will try different approaches. They often will
use another method to check their answers.
2. Reason abstractly and quantitatively.
Third graders should recognize that a number represents a specific quantity. They connect the
quantity to written symbols and create a logical representation of the problem at hand,
considering both the appropriate units involved and the meaning of quantities.
3. Construct viable arguments and critique the reasoning of others.
In third grade, students may construct arguments using concrete referents, such as objects,
pictures, and drawings. They refine their mathematical communication skills as they participate
in mathematical discussions involving questions like “How did you get that?” and “Why is that
true?” They explain their thinking to others and respond to others’ thinking.
4. Model with mathematics.
Students experiment with representing problem situations in multiple ways including numbers,
words (mathematical language), drawing pictures, using objects, acting out, making a chart, list,
or graph, creating equations, etc. Students need opportunities to connect the different
representations and explain the connections. They should be able to use all of these
representations as needed. Third graders should evaluate their results in the context of the
situation and reflect on whether the results make sense.
5. Use appropriate tools strategically.
Third graders consider the available tools (including estimation) when solving a mathematical
problem and decide when certain tools might be helpful. For instance, they may use graph
paper to find all the possible rectangles that have a given perimeter. They compile the
possibilities into an organized list or a table, and determine whether they have all the possible
rectangles
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6. Attend to precision.
As third graders develop their mathematical communication skills, they try to use clear and
precise language in their discussions with others and in their own reasoning. They are careful
about specifying units of measure and state the meaning of the symbols they choose. For
instance, when figuring out the area of a rectangle they record their answers in square units.
7. Look for and make use of structure.
In third grade, students look closely to discover a pattern or structure. For instance, students
use properties of operations as strategies to multiply and divide (commutative and distributive
properties).
8. Look for and express regularity in repeated reasoning.
Students in third grade should notice repetitive actions in computation and look for more
shortcut methods. For example, students may use the distributive property as a strategy for
using products they know to solve products that they don’t know. For example, if students are
asked to find the product of 7 x 8, they might decompose 7 into 5 and 2 and then multiply 5 x 8
and 2 x 8 to arrive at 40 + 16 or 56. In addition, third graders continually evaluate their work by
asking themselves, “Does this make sense?”
Use place value understanding and properties of operations to perform multi‐digit arithmetic.
MCC3.NBT.1 Use place value understanding to round whole numbers to the nearest 10 or 100.
MCC3.1.NBT.2 Fluently add and subtract within 1000 using strategies and algorithms based on
place value, properties of operations, and/or the relationship between addition and
subtraction.
Solve problems involving the four operations, and identify and explain patterns in arithmetic.
MCC3.OA.8 Solve two‐step word problems using the four operations. Represent these
problems using equations with a letter standing for the unknown quantity. Assess the
reasonableness of answers using mental computation and estimation strategies including
rounding.
MCC3.OA.9 (only addition table in Unit 1) Identify arithmetic patterns (including patterns in
the addition table or multiplication table), and explain them using properties of operations. For
example, observe that 4 times a number is always even, and explain why 4 times a number can
be decomposed into two equal addends.
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Overview
This unit works to develop ideas about the meaning of operations with whole numbers, the
growth of computational fluency, and the structure of place value and the base‐ten number
system. Students will expand their understanding to focus on addition and subtraction, within
1,000, using strategies (including rounding) and algorithms that are based on place‐value,
properties of operations, and/or the relationship between addition and subtraction. Students
will use these strategies to solve 1‐and 2‐step problems.
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Evidence of Learning
What Students Should Know:
MCC3.NBT.1
Estimating numbers is asking questions like, “What tens are 32 between and which one is it closer to?”
One way to estimate is rounding up to a nearby number when a number has a 5 or more and rounding down to a nearby number if a number is 4 or less.
Estimation is used when you don’t need an exact answer. Estimation can be used to assess the reasonableness of solutions.
MCC3.1.NBT.2
Place value is a base ten system of grouping sets of ten notated by correct placement of digits.
Place value increases from the right to the left. Place value names (starting from the right) = ones, tens, hundreds, thousands. Each place value can be categorized as a set. The ones place are single units; the tens
place are groups of tens; hundreds place are groups of hundreds etc. Making a ten is a mental math strategy which groups numbers in sets of ten. Adding 9 is a mental math strategy which is think of 9 as a ten and subtract 1. Give and Take strategy allows you to take from one number and give the same amount
to another number to make it easier to add. Grouping compatible numbers makes adding easy. Ex. Combining doubles; making a ten
etc. Counting on is a mental math strategy where students count on from the larger
numbers. Subtracting 9 is a mental math strategy which you subtract ten and then add on one. Counting back on the number line is a strategy for subtraction where you start at the
larger number and count backwards. Counting up is a mental math strategy for subtraction where you use the number line
and begin at the smaller number and count up to the larger number. Subtracting easy numbers helps to subtract more quickly. 150‐18; first subtract the 10,
and then subtract the 8. The commutative property (order) for addition states that the order of the addends
does not change the sum. a+b=b+a The identity property of addition states that any addend plus zero equals the addend.
4+0=4 The associative property of addition states that the sum stays the same when the
grouping of addends is changed. (3+4)+2=9 or 3+(4+2)=9 The commutative and associative properties do not apply to subtraction.
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Any time zero is subtracted from a number the difference is the number. Addition and subtraction are inverse operations.
MCC3.0A9
Addition and subtraction can be used to solve problems. Other strategies such as making a list, drawing a picture, using a model, using a number
line, etc. can also be used to solve addition and subtraction word problems. Adding two even numbers or two odd numbers always results in an even sum. Adding an even number and an odd number always results in an odd sum.
What Students Should Be Able To Do:
MCC3.NBT.1
Use place value understanding to round numbers to the nearest 10 or 100
Identify when estimation is useful and when an exact number is needed
Estimate the relative size of a number and ways to represent them
Use a number line to visualize the placement of the number and/or ask questions such as: “What tens are 32 between and which one is it closer to?”
MCC3.1.NBT.2
Add and subtract within 1000
Achieve fluency with strategies and algorithms that are based on place value, properties of operations, and/or the relationship between addition and subtraction
Perform inverse operations for addition and subtraction
Compare numbers based on place value and the base ten
Add and subtract numbers using the properties
Identify the properties of addition and subtraction
Create models of the properties of addition and subtraction
Check computation using inverse properties
MCC3.0A9
Use mental math strategies to quickly solve addition and subtraction problems
Use estimation to solve addition and subtraction problems
Add and subtract whole numbers in the context of a problem solving situation
Choose the appropriate operation (addition/subtraction) when solving word problems
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Suggested Essential Questions
Essential questions will be created by the teacher and posted with every lesson. The following
are a few exemplar essential questions that may be utilized by the teacher.
MCC3.NBT.1
How does the placement of a digit change the value of a number?
Explain how to round a number to the nearest 10 or 100?
When is it appropriate to round numbers?
MCC3.1.NBT.2
How are addition and subtraction related?
What strategy can I use to add mentally?
What strategy can I use to subtract mentally?
How can I use place value to add numbers?
How can I use place value to subtract numbers?
MCC3.OA.8
How do you know when to use addition or subtraction to solve a problem?
When do you use addition or subtraction in everyday life?
MCC3.OA.9
What patterns do you see in an addition table?
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Vocabulary Elementary Students almost never learn new words effectively from definitions. Virtually all of their vocabulary is acquired from use in context. Children build their own “working definition” based on their initial experiences and continue to work with ideas before they develop a formal definition. Vocabulary lessons might include building an illustrated word wall, finding non‐examples of the word, explaining the word to another student, using manipulatives to show understanding of the concept. Add Addends Base Ten Difference Digits Equation Estimate Even Numbers Fact Family Inverse Mental Math Odd Numbers Operations Place Value Rounding Sum Associative (grouping) Property of Addition Commutative (order) Property of Addition Identity (zero) Property of Addition
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Suggested Strategies for Teaching and Learning
Common Core Georgia Performance Standard
Misconception
MCC3.NBT.1 Use place
value understanding to
round whole numbers to
the nearest 10 or 100.
The use of terms like “round up” and “round down” confuses many students. For example, the number 37 would round to 40 or they say it “rounds up”. The digit in the tens place is changed from 3 to 4 (rounds up). This misconception is what causes the problem when applied to rounding down. The number 32 should be rounded (down) to 30, but using the logic mentioned for rounding up, some students may look at the digit in the tens place and take it to the previous number, resulting in the incorrect value of 20. To remedy this misconception, students need to use a number line to visualize the placement of the number and/or ask questions such as: “What tens are 32 between and which one is it closer to?” Developing the understanding of what the answer choices are before rounding can alleviate many misconceptions and confusions related to rounding.
If students have difficulty rounding to the nearest hundred, have them draw a line under the rounding place and a square around the digit to the right of this place.
Make sure students understanding how to round in the context of a word problem. For example: Ms. Henry needs to buy cups for a school party. Cups come in packs of 10 and she has 243 students. How many packs does she need to buy? In this story, students will need to round to 250 in order to have enough cups for all the students.
Students should round the addends to get an estimated sum. They should not add the addends and then round the sum. The same holds true for subtraction.
MCC3.NBT.2 Fluently add
and subtract within 1000
using strategies and
algorithms based on place
value, properties of
operations, and/or the
relationship between
addition and subtraction.
If students cannot use place‐value patterns to find sums and differences mentally, have them use place‐value blocks or point to the numbers on a 1,000’s chart as they add or subtract.
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Use place value understanding and properties of operations to perform multi‐digit arithmetic.
MCC3.NBT.1 ‐ Use place value understanding to round whole numbers to the nearest 10 or
100.
3.MP.2 Reason abstractly and quantitatively.
3.MP.4 Model with mathematics.
Additional Lessons:
The Island Hop
The Great Round Up
Field Day Fun
I Have a Story, You Have a Story
Children’s Literature:
Moira’s Birthday, by Robert Munsch: Moira wants to have a birthday party and invite all of the
children in the school. And, without her parents' knowledge or consent, she does. What follows
provides readers with a humorous look at estimation and problem solving. ISBN: 0920303838
Hands on Standards:
Number and Operations Lesson 4: Estimating the Sum or Difference
Students will begin to understand that sometimes a situation calls for an estimate
rather than exact answer. Estimates are helpful when dealing with very large
numbers. (Note: Use this lesson to model how to round numbers in the context of a
word problem. Explain that estimates are helpful when dealing with very large
numbers or when an exact answer is not needed.)
Scott Foresman, Volume 1
Lesson 1‐2 Numbers in the Hundreds, p. 6 (Note: Standard expanded and written forms
are not part of the third grade standard. This lesson could be used as a review of
determining the values of digits in a given place.)
Lesson 1‐3 Place Value Patterns, p. 8 (Note: This lesson can be used to activate
students’ prior knowledge of using place value to write numbers in different but
equivalent forms.)
Lesson 1‐10 Rounding Numbers, p. 28
Lesson 2‐7 Estimating Sums, p. 86 (Note: Compatible numbers and front‐end
estimation is not a part of this standard.)
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Lesson 2‐11 Estimating Differences, p. 98
MCC3.1.NBT.2 ‐ Fluently add and subtract within 1000 using strategies and algorithms based
on place value, properties of operations, and/or the relationship between addition and
subtraction.
3.MP.2 Reason abstractly and quantitatively.
3.MP.4 Model with mathematics.
3.MP.5 Use appropriate tools strategically.
Additional Lessons
Shake, Rattle, and Roll
Happy to Eat Healthy
Mental Mathematics
Perfect 500!
Take 1,000
The Power of Properties
Take Down
Children’s Literature
Dealing with Addition, Lynette Long: Author Lynette Long walks kids through a deck of
cards. Then she invites them to put cards in groups, match pairs, and add cards together
in different combinations to make the number ten. All that is good math practice, but in
this case it's also setting the stage for a new card game that Long has created: Dealing
with Addition. ISBN: 9780881062700
Alexander, Who Used to be Rich Last Sunday, by Judith Viorst: Poor Alexander. His
grandparents gave him one dollar when they came to visit, and now he has nothing to
show for it but a deck of cards with two cards missing, a one‐eyed bear, a melted
candle, and bus tokens.
Also may be used when teaching subtraction. ISBN: 9780689711992
Hands on Standards
Numbers and Operations Lesson 3: Adding and Subtracting
Students will learn the fundamentals of adding and subtracting numbers up to
four digits with and without regrouping.
Algebra Lesson 7: Associative Property of Addition
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Students will find that the associative property of addition allows them to add
compatible numbers more easily by regrouping as a series of addends when
finding the sum.
Numbers and Operations Lesson 5: Commutative Property of Addition
Students may mistakenly think that they can use the commutative property to
switch any two numbers in an addition problem. Reaffirm that only the addends
can shift places without changing the problem.
Algebra Lesson 11: Addition and Subtraction
Students will address equations that have an unknown number and learn to
work backwards by using the inverse operation to solve for the missing number.
NLVM
The following activities can be used to reinforce the skills in this unit. For a detailed explanation
on how to use the activities, please click on the instructions button at the top right of the page.
Numbers and Operations (Grades 3‐5)
Base Blocks Addition
Base Blocks Subtraction
Super Source
Place It In this game for two to four players, children each roll number cubes and then make a 2‐digit number from the digits rolled. They represent that number with units and longs in an effort to be the one who accumulates blocks with the total value closest to 100. In this activity, children have the opportunity to:
do mental computation
develop strategic thinking skills
Choose a Place
In this game for two to four players, children represent each roll of a number cube with units or longs in an effort to collect Base Ten Blocks with a total value of 100. In this activity, children have the opportunity to:
understanding of place value
use addition
develop strategic develop
thinking skills
Clear the Mat
In this game for teams of two, children roll a number cube to determine the value of the Base Ten Blocks to remove from their place‐value mats. They look for a strategy for being the first team to remove all the blocks from their mat. In this activity, children have the opportunity to:
Page 12 of 16
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use estimation skills
use subtraction
develop strategic thinking skills
1,000 More or Less
Children model a 3‐digit starting number with Base Ten Blocks. They roll number cubes to help them determine another 3‐digit number that, when added to the starting number, will result in a sum that is close to 1,000. In this activity, children have the opportunity to:
find missing addends
develop strategies for adding 3‐digit numbers
use logical reasoning
build mental math skills
Recommended sections of Teaching Student‐Centered Mathematics Grades 3‐5
Chapter 2: Number and Operation Sense: This chapter includes activities that allow
students to view, estimate, and compare numbers in a variety of ways. The book also
includes real‐world context problems to help with the understanding of place value. The
suggested activities include the use of hundreds and thousands charts. There are several
other activities that assist with number sense and using the properties of addition and
subtraction to compute.
Chapter 3: Helping Children Master The Basic Facts: This chapter assists students with
developing a strong understanding of number relationships of operations, efficient
strategies for fact retrieval through practice, and drills in the use and selection of those
strategies once they have been developed. There are also several activities that allow
students to apply the skills and solve addition and subtraction problems.
Chapter 4: Strategies For Whole‐Number Computation: This chapter provides flexible
methods of computation involving taking apart and combining numbers in a variety of
ways. It also discusses way to allow students to use invented strategies for addition and
subtraction.
Scott Foresman, Volume 1
Lesson 2‐1 Properties of Addition, p. 66 (Note: Review properties of addition with
students and explain that there are relationships for whole numbers and addition that
always hold true; these help simplify calculations.)
Lesson 2‐2 Relating Addition and Subtraction, p. 70 (Note: Use this lesson as a review of
fact families and why addition and subtraction are inverse operations; you can use
addition to solve subtraction problems.)
Lesson 2‐5 Mental Math: Break Apart Numbers, p. 80
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Lesson 2‐6 Mental Math: Using 10s to Add, p. 82
Lesson 2‐9 Mental Math: Using Tens to Subtract, p. 94
Lesson 2‐10 Mental Math: Counting on to Subtract, p. 96
Lesson 3‐1 Adding Two‐Digit Numbers, p. 126
Lesson 3‐2 Models for Adding Three‐Digit Numbers, p. 128
Lesson 3‐6 Regrouping, p. 146
Lesson 3‐7 Subtracting Two‐Digit Numbers, p. 148
Lesson 3‐8 Models for Subtracting Three‐Digit Numbers, p. 150
Lesson 3‐9 Subtracting Three‐Digit Numbers, p. 152
Lesson 3‐10 Subtracting Across Zero, p. 156
Solve problems involving the four operations, and identify and explain patterns in arithmetic.
MCC3.OA.8 ‐ Solve two‐step word problems using the four operations. Represent these
problems using equations with a letter standing for the unknown quantity. Assess the
reasonableness of answers using mental computation and estimation strategies including
rounding.
3.MP.1 Make sense of problems and persevere in solving them.
3.MP.3 Construct viable arguments and critique the reasoning of others.
3.MP.6 Attend to precision
Additional Lessons
Armadillo Stories
Hooked on Solutions
Children’s Literature
The Five Hundred Hats of Bartholomew Cubbins, by Dr. Seuss: We know from the title
that there are going to be 500 hats. Neither Bartholomew nor the King are aware of
that. This insider information lets us view the action differently and we begin counting
almost immediately. Because not every hat from 1 to 500 is visible to us, we are forced
to count around the gaps to make the book make sense. Filling in missing information
seems like math to me. ISBN: 0825436184
Weighing the Elephant by Ting‐xing Ye and Suzane Langlois: Estimation and problem
solving can be approached through this book. The villagers must use both those skills to
accomplish the seemingly impossible task of figuring out an elephant's exact weight
without access to a large scale. ISBN: 9781550375268
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Scott Foresman, Volume 1
Lesson 1‐11 Plan and Solve, p.32 (Note: Use this lesson to activate students’ prior
knowledge of determining what questions they should ask when they are trying to read
and understand a word problem.)
Lesson 2‐8 Overestimates and Underestimates, p. 90
Lesson 2‐12 Writing to Explain, p. 102
Lesson 3‐5 Draw a Picture, p. 140 (Note: To be used when solving problems.)
Lesson 3‐11 Exact Answer or Estimate, p. 160 (Note: This lesson can be used to illustrate
adding and subtracting exact or estimated results to solve problems in real world
contexts.)
Lesson 3‐13 Choose a Computation Method, p. 166
Lesson 3‐15 Problem‐Solving Applications, p. 170 (Note: Use the reteaching, practice,
enrichment, and problem solving exercises as a review of key concepts, skills and
strategies discussed in this unit. )
MCC3.OA.9 (only addition table in Unit 1) Identify arithmetic patterns (including patterns in
the addition table or multiplication table), and explain them using properties of operations.
For example, observe that 4 times a number is always even, and explain why 4 times a
number can be decomposed into two equal addends.
3.MP.7 Look for and make use of structure.
3.MP.8 Look for and express regularity in repeated reasoning.
Additional Lessons
Skip‐Counting Patterns
Take The Easy Way Out
Exemplars
Penny a Day
A Broken Gumball Machine
Building Towers
NLVM
The following activities can be used to reinforce the skills in this unit. For a detailed explanation
on how to use the activities, please click on the instructions button at the top right of the page.
Page 15 of 16
Third grade Unit 1 5/17/12
Numbers and Operations (Grades 3‐5)
Hundreds Chart
Scott Foresman, Volume 1
Lesson 1‐9 Number Patterns, p. 24
Lesson 2‐3 Find a Rule, p. 72
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