Unit 5
Addition and Subtraction up to 20
First Grade
5E Lesson Plan Math
Grade Level: 1st
Subject Area: Math
Lesson Title: Unit 5 Addition and
Lesson Length: 15 days
Subtraction up to 20
THE TEACHING PROCESS
Lesson Overview
This unit bundles student expectations that address representing and solving
addition and subtraction problem situations by applying basic fact strategies and
properties of operations. According to the Texas Education Agency, mathematical
process standards including application, tools and techniques, communication,
representations, relationships, and justifications should be integrated (when
applicable) with content knowledge and skills so that students are prepared to use
mathematics in everyday life, society, and the workplace.
During this unit, students extend representing and solving contextual or real-world
problem situations involving sums and minuends up to 20 using spoken words,
objects, pictorial models, and number sentences. They explore and explain a
variety of strategies to solve problems involving action (joining and separating
problems), and problems involving no action (part-part-whole and comparing
problems). While demonstrating various strategies, students explore and apply
properties of operations. Students are expected to use a number sentence to
represent the problem and explain that the equal sign represents a relationship
where expressions on each side of the equal sign represent the same value(s).
Through the use of continued experiences with addition and subtraction situations,
students begin to recognize basic fact relationships, which are essential for
developing computational fluency. They also apply composition and
decomposition of numbers to determine the unknown whole number when the
unknown may be any one of the three of four terms in the equation. Within this
unit, students also experience generating addition and subtraction situations when
given a number sentence involving addition or subtraction of numbers within 20.
Thorough understanding of analyzing problems and using the problem-solving
process in addition and subtraction situations involving sums and minuends up to
20 is critical in setting the foundation for students’ success in mathematics as they
progress through future grade levels.
Unit Objectives:
Students will…
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extend representing and solving contextual or real-world problem situations
involving sums and minuends up to 20 using spoken words, objects, pictorial
models, and number sentences.
explore and explain a variety of strategies to solve problems involving action
(joining and separating problems), and problems involving no action (part1
Unit 5
Addition and Subtraction up to 20
First Grade
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part-whole and comparing problems).
demonstrating various strategies, students explore and apply properties of
operations.
use a number sentence to represent the problem and explain that the equal
sign represents a relationship where expressions on each side of the equal
sign represent the same value(s).
recognize basic fact relationships, which are essential for developing
computational fluency.
apply composition and decomposition of numbers to determine the unknown
whole number when the unknown may be any one of the three or four terms
in the equation.
generate addition and subtraction situations when given a number sentence
involving addition or subtraction of numbers within 20.
analyze problems and using the problem-solving process in addition and
subtraction situations involving sums and minuends up to 20 is critical in
setting the foundation for students’ success in mathematics as they progress
through future grade levels.
Standards addressed:
TEKS:
1.1A
Apply mathematics to problems arising in everyday life, society, and the
workplace.
1.1B
Use a problem-solving model that incorporates analyzing given information,
formulating a plan or strategy, determining a solution, justifying the solution, and
evaluating the problem-solving process and the reasonableness of the solution.
1.1C
Select tools, including real objects, manipulatives, paper and pencil, and
technology as appropriate, and techniques, including mental math, estimation, and
number sense as appropriate, to solve problems.
1.1D
Communicate mathematical ideas, reasoning, and their implications using multiple
representations, including symbols, diagrams, graphs, and language as
appropriate.
1.1E
Create and use representations to organize, record, and communicate
mathematical ideas.
1.1F
Analyze mathematical relationships to connect and communicate mathematical
ideas.
1.1G
Display, explain, and justify mathematical ideas and arguments using precise
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Unit 5
Addition and Subtraction up to 20
First Grade
mathematical language in written or oral communication.
1.3E
Explain strategies used to solve addition and subtraction problems up to 20 using
spoken words, objects, pictorial models, and number sentences.
1.3F
Generate and solve problem situations when given a number sentence involving
addition or subtraction of numbers within 20.
1.5D
Represent word problems involving addition and subtraction of whole numbers up
to 20 using concrete and pictorial models and number sentences.
1.5E
Understand that the equal sign represents a relationship where expressions on
each side of the equal sign represent the same value(s).
1.5F
Determine the unknown whole number in an addition or subtraction equation when
the unknown may be any one of the three or four terms in the equation.
1.5G
Apply properties of operations to add and subtract two or three numbers.
ELPS:
ELPS.c.1C
use strategic learning techniques such as concept mapping, drawing, memorizing,
comparing, contrasting, and reviewing to acquire basic and grade-level vocabulary
ELPS.c.2I
demonstrate listening comprehension of increasingly complex spoken English by
following directions, retelling or summarizing spoken messages, responding to
questions and requests, collaborating with peers, and taking notes commensurate
with content and grade-level needs.
ELPS.c.3B
expand and internalize initial English vocabulary by learning and using highfrequency English words necessary for identifying and describing people, places,
and objects, by retelling simple stories and basic information represented or
supported by pictures, and by learning and using routine language needed for
classroom communication
ELPS.c.3C
speak using a variety of grammatical structures, sentence lengths, sentence types,
and connecting words with increasing accuracy and ease as more English is
acquired
ELPS.c.3D
speak using grade-level content area vocabulary in context to internalize new
English words and build academic language proficiency
ELPS.c.3H
narrate, describe, and explain with increasing specificity and detail as more
English is acquired
Misconceptions:
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Unit 5
Addition and Subtraction up to 20
First Grade
Some students may think they must add or subtract in the order that the numbers
are presented in the problem rather than performing the operation based on the
meaning and action(s) of the problem situation.
Some students may think subtraction is commutative rather than recognizing the
minuend as the total amount and the subtrahend as the amount being subtracted
(e.g., 5 – 3 is not the same as 3 – 5, etc.).
Some students may think the equal sign means that an operation must be
performed on the numbers on one side and the result of this operation is recorded
on the other side of the equal sign rather than understanding that operations
and/or individual numbers can be on either side of the equal sign as long as they
represent equal quantities.
Underdeveloped Concepts:
Some students may not recognize the difference between an addition situation
and a subtraction situation based on the context of the problem.
Some students may confuse the –, +, and = symbols due to not fully
understanding the meaning of each symbol.
Some students may correctly determine related addition number sentences, but
have difficulty determining the subtraction number sentences within a fact family.
Vocabulary:
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Addend – a number being added or joined together with another number(s)
Additive identity – the sum/difference is not affected when zero is
added/subtracted to a number
Associative property of addition – if three or more addends are added,
they can be grouped in any order, and the sum will remain the same
Commutative property of addition – if the order of the addends are
changed, the sum will remain the same
Compose numbers – to combine parts or smaller values to form a number
Counting (natural) numbers – the set of positive numbers that begins at
one and increases by increments of one each time {1, 2, 3, ..., n}
Decompose numbers – to break a number into parts or smaller values
Difference – the remaining amount after the subtrahend has been
subtracted from the minuend
Equal sign – a mathematical symbol representing equivalence
Equation – a mathematical statement composed of equivalent expressions
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Addition and Subtraction up to 20
First Grade
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separated by an equal sign
Expression – a mathematical phrase, with no equal sign, that may contain
a number(s), an unknown(s), and/or an operator(s)
Fact families – related number sentences using the same set of numbers
Minuend – a number from which another number will be subtracted
Number sentence – a mathematical statement composed of numbers,
and/or an unknown(s), and/or an operator(s), and an equality or inequality
symbol
Strip diagram – a linear model used to illustrate number relationships
Subtrahend – a number to be subtracted from a minuend
Sum – the total when two or more addends are joined
Term – a number and/or an unknown in an expression separated by an
operation symbol(s)
Whole numbers – the set of counting (natural) numbers and zero {0, 1, 2,
3, ..., n}
Related Vocabulary:
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Addition
Addition symbol
Change unknown
Combination
Compare
Join
Minus
Model
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Operation
Part-part-whole
Plus
Quantity
Reasonable
Relationship
Result unknown
Separate
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Solution
Start unknown
Strategy
Subtraction
Subtraction symbol
Total
Unknown
Value
List of Materials:
Animals on Board by Stuart J. Murphy
The Hershey’s Kisses Addition Book by Jerry Pallotta
Dry Erase Board
Dry Erase Marker
Student Materials:
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Unit 5
Addition and Subtraction up to 20
First Grade
Deck of cards (20 cards each)
Pencil
Manipulative (various, if needed)
Number Line
100 Chart
Flash cards
Resource Sheets:
 Resource Sheet 1A&B: Tiger & Elephant Picture Cards
 Animals on Board by Stuart J. Murphy
 Resource Sheet 2: Part-Part-Total Mat
 Resource Sheet 3A&B: Number Cards
 Resource Sheet 4: Additional Story Problems – Result or Total Unknown
 Resource Sheet 5: Additional Story Problems – Change or Addend
Unknown
 Resource Sheet 6: Additional Story Problems – Start Unknown
 Resource Sheet 7: Additional Story Problems – Compare
 Resource Sheet 8: Ace of Number Game
 Resource Sheet 9: Teacher Checklist
 Resource Sheet 10: Exit Ticket
 Resource Sheet 11A&B: How Many More/How Many Fewer
 Mixed Math Worksheets
INSTRUCTIONAL SEQUENCE
All lesson maybe repeated in Small group where needed
Phase 1 : Engage the Learner
Materials:
Math Journals
Two-Color Counters
Day 1 Activity:
Distribute two-color counters to each student. Ask the students to make as many
different combinations for 10 using the counters as they can and record them in
their Math Journals. Those who struggle with this activity may need additional
experience and support prior to the lesson. Bring the lesson back to Whole Group
and discuss the students’ findings.
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Addition and Subtraction up to 20
First Grade
What combinations equal 10 as the sum?(record solutions)
What’s the teacher doing?
What are the students doing?
Monitoring the students’ understanding
of addition to 10.
Using counters to make combinations
that add to 10.
Assisting students in making correct
combinations.
Phase 1 :Engaging the Learners
Day 2
Materials:
Resource Sheets 1A&B
Math Journals
Activity:
Pass out picture cards of two different animals (Resource Sheets 1A&B). Students
will role-play through the story problem pretending to be the animals. Teacher
should lead a discussion of what is taking place and highlight math vocabulary
such as join together, add to. Prompt students to generate a numeric equation to
answer the question “How many animals are there?” two
Read the following story problem:
There were four tigers in the grass and three elephants in the river. How many
animals are there in all?
Have four students who are holding the tiger pictures come to the front of the room
along with three students who are holding the elephant pictures. Ask them to act
out the problem as you reread it. Ask the class to discuss the solution. Ask how
they would write an equation to represent this story. Be sure to share both
possibilities:
•4+3= ?
•?=4+3
Repeat this activity with use of different numbers. Students will create equations
using the picture cards.
Students should write the responses in their Math Journals
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Addition and Subtraction up to 20
First Grade
What’s the teacher doing?
What are the student’s doing?
Monitoring Students for comprehension
Listening and creating number
sentences
Identifying vocabulary from unit
Phase 1 Engage the Learner Day 3
Materials:
The Hershey’s Kisses Addition Book by Jerry Pallotta
Activity:
The lesson will begin on the carpet (or meeting spot). The teacher will be sitting in
front of the carpet on a chair for the read aloud. A dry erase board will be
accessible to the teacher. Students will return to their desks to work with a partner.
Students will return to the rug for sharing and assessment.
Read the book The Hershey’s Kisses Addition Book, by Jerry Pallotta, aloud
pausing frequently to add up the illustrations. Allow students to add up the
illustrations that amount to more than 10. At the conclusion of the book,
Which strategy the book was using to add two numbers together? Counting
on
Can remember some of the addition facts in the book? List responses on
board
Write the number sentence on the dry erase board, and solve it by drawing a
picture.(Students will also write this in their journals)
Use the picture to demonstrate the counting on strategy.
Ask students to:
Demonstrate and explain what else I could do to solve the addition problem (use
100 counting chart, or cubes/beans, or a number line, etc.). Demonstrate
whichever strategy students suggest. Ask for volunteers to solve addition
problems using a “counting on” strategy.
What’s the teacher doing?
What are the students doing?
Reading the book pausing to add
illustrations
Calling on students to demonstrate and
explain the following strategies.
Listening to story
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Counting on
100 chart
Adding Illustrations
Demonstrating and explaining solving
problems with the following strategies.
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Addition and Subtraction up to 20
First Grade
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# line
manipulatves
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Counting on
100 chart
# line
manipulatves
Phase 2 Explore the Concept Day 4
Materials:
Manipulatives (20 to each student)
Resource Sheet 2: Part-Part-Total Mat (one for each student)
Resource Sheet 3: Number Cards
dry erase marker (one for each student)
Activity:
Display this word problem for students on chart paper or an interactive
whiteboard. It is NOT expected that the students would name the type of
problem. Their job is to make sense of each problem and solve it. For a full
listing of problem types, see:
http://www.corestandards.org/assets/CCSSI_Math%20Standards.pdf
Example 1:
A truck was carrying 7 horses. Another truck passed by carrying 4 horses. How
many horses were on both trucks?
Allow time for ‘Think-Pair-Share’ prior to students working on the problem to help
them visualize and comprehend what is essential for them to solve.
Think-Pair-Share Discussion Questions:
While leading this discussion, incorporate the use of visuals or models.
• How many trucks are there?
• What is on each truck?
• What are we solving for? (Be sure you help students identify that the unknown
can be represented with a box or a question mark.)
• What is our unknown? (Show students a box or question mark that highlights
that this is the unknown.)
Distribute manipulatives and Resource Sheet 2: Part-Part-Total Mat to each
student. While students are working to solve the problem, the teacher should
monitor student progress.
The teacher should then prompt students to use Resource Sheet 3: Number
Cards or dry erase markers to record numbers in the form of an equation on their
part-part-total mats. (It would work best to laminate the part-part-total mats or
place them in a sleeve. See Resource Sheet 2: Part-Part-Total Mat.)
The teacher should then initiate a discussion with the whole class, identifying
equations created by the students and highlighting the vocabulary terms of ‘joining
together’ and ‘sum’.
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Unit 5
Addition and Subtraction up to 20
First Grade
What are you solving for? Sum
How are the numbers represented on your part-part-total mat? Answers vary
What is the missing number? Answers vary
What’s the teacher doing?
What are the students doing?
Facilitating questions
Students will demonstrate the solution for
the word problem using manipulatives or
some virtual representation.
Monitoring for comprehension
Phase 2 Exploring the Concept Day 5
Materials:
dry erase markers (one for each student)
Resource Sheet 3A&B (one set for each student)
Resource Sheet 4
Resource Sheet 9: Teacher Checklist.
Resource Sheet 10: Exit Ticket
Activity:
Teacher presents the following word problem.
There were 11 black bears at the zoo. 5 of the bears took a nap. How many bears
How this problem is different from the first one?
What operation would you use the find the answer?
Could you use either addition or subtraction? (Students should see that you
could use either 11 – 5 =? or 5 +? = 11.
Allow time for students to solve the problem and share their solutions.
Using Resource Sheet 3A&B: Number Cards or dry erase markers to record the
equation for their solution.
Allow time for students to share these equations.
(Open-ended problem with more than one solution)
Some bears were sitting under a big tree. 3 bears came over to join them.
How many bears are under the big tree now?
Allow time for students to create as many different solutions as they can, recording
them in pictures and/or equations. Allow time for students to share their solutions.
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Addition and Subtraction up to 20
First Grade
Record a ‘Class Set of Solutions’ to display for future reference.
Have all the possible solutions been found? (discuss different responses)
Several more story problems may be used to provide students with more practice,
if needed. See Resource Sheet 4 for additional ‘Result or Total Unknown’ story
problems.
Formative Assessment:
Observe students as they work. Record your findings on Resource Sheet 9:
Teacher Checklist.
Distribute Resource Sheet 10: Exit Ticket to each student.
What’s the teacher doing?
What are the students doing?
Monitoring students for understanding.
Using manipulatives to solve problem.
Verbally giving equation and using
correct vocabulary from unit
Asking questions.
Phase 2 Exploring the Concept
Day 6
Materials:
manipulatives
part-part-total mats
Day 6 Activity:
Students will work to solve ‘Start Unknown’ problems.
Pose the following problem to the students and allow time for them to share their
thinking.
Example 1:
The red truck headed to the circus with some bears on it. The green truck headed
to the circus with 3 bears on it. A total of 11 bears are headed to the circus. How
many bears are on the red truck?
Ask students to share what they know from hearing the problem. Allow time for
them to share their thinking.
Then ask what they need to find. Again, allow time for the students to share their
ideas.
Provide time for them to use their manipulatives and part-part-total mats to explore
the problem and arrive at a solution.
Again, allow time for students to share their different strategies and solutions with
partners and/or the whole group.
Finally, ask the students if their answer could be more than the 11 bears being
taken to the circus. Why or why not?
Teachers should record appropriate strategies on a chart for students to refer back
to at a later time when solving problems of similar types.
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Addition and Subtraction up to 20
First Grade
Allow time for students to write an equation to represent the problem.
Example 2:
There was a basket of apples in the bear cage. The bears ate 5 apples. There
were 7 apples left in the basket. How many apples were in the basket before
they started eating?
Repeat procedure from above, allowing time for students to share their solutions
and reasoning.
What’s the teacher doing?
What are the student’s doing?
Monitoring students for understanding.
Working equations.
Sharing solutions and reasoning.
Phase 3 Explain the Concept and Define the Terms Day 7
Materials:
manipulatives
part-part-total mats
Activity:
Students will work to solve ‘Compare’ problems.
Pose the following problem to the students and allow time for them to share their
thinking.
Example 1:
There were 14 bears on the red truck and 8 bears on the green truck.
Allow time for students to solve the problem using manipulatives and the part-parttotal mat. Ask them to record their solutions using an equation. Ask if the solution
could be a number larger than 14. Have students share the strategies they used to
arrive at their solutions. Discuss the fact that they are comparing the number of
bears in each truck.
Example 2:
The bears were eating lunch one day at the zoo. The brown bear had 3 apples left
and the black bear had 7 apples left to eat. How many fewer apples does the
brown bear have left to eat than the black bear?
Again, allow time for students to solve the problem using manipulatives and the
part-part-total mat. Ask them to record their solutions using an equation. Ask if the
solution could be a number larger than 7. Have students share the strategies they
used to arrive at their solutions. Discuss the fact that they are comparing the
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Unit 5
Addition and Subtraction up to 20
First Grade
number of apples each bear has left.
Refresh students of unit vocabulary
What’s the teacher doing?
What are the students doing?
Observing and monitoring students for
understanding.
Working equation using manipulatives.
Solving and explaining the results.
Using related unit vocabulary.
Phase 3 Explain the Concept and Define the Terms Day 8
Materials:
Animals on Board by Stuart J. Murphy
Activity:
Read story: Animals on Board by Stuart J. Murphy or any book that relates to
animals and addition and subtraction methods.
Highlight pages 9 and 13 and discuss the pictures and equations to incorporate
math vocabulary such as ‘sum’ and ‘joining together’.
Students will write in their journal the definitions of vocabulary in their own words.
What’s the teacher doing?
What are the students doing?
Reading story and concentrating on
vocabulary.
Actively listening to story.
Defining vocabulary in own terms.
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Addition and Subtraction up to 20
First Grade
Phase 4 Elaborate on the Concept Day 9
Materials:
Flash Cards with sums and differences up to 20
Activity:
Flash Card Day!
Divide students into partners. Give each set of two flash cards mixed with addition
and subtraction equations up to 20. Have each set of students work with their
partner on identifying the solution to the equation on the flash card. Rotate
partners.
What’s the teacher doing?
What are the students doing?
Observing and monitoring for
understanding and participation.
Working with partner to solve addition
and subtraction equations shown on flash
cards.
Phase 4 Elaborate on the Concept
Day 10
Activity:
Complete Mixed Math Worksheet using manipulatives.
Ask/Review:
Does the order of addend affect the sum?
What is an addend?(vocabulary review)
What’s the teacher doing?
What are the students doing?
Monitoring and observing for
understanding and correct usage of the
manipulatives.
Completing worksheet with the use of
manipulatives.
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Addition and Subtraction up to 20
First Grade
Phase 4 Elaborate on the Concept
Day 11
Activity:
Stations: As soon as math beings assign each student to a group. Clearly state
the routines and procedures of the station rotation and expectations of the
students while in stations.
Prepare 4-5 Addition/Subtraction stations with clear directions of assignment.
After each statement student should turn in assessment of the station.
Stations may vary by district below are two examples:
Bowling Alley Subtraction Station
Using recycled two liter bottles (pin) and small ball (bowling ball) Have students
bowl and subtract from 10 the number of pins (two liter bottles) they knock down.
To challenge the students different numbers can be attached to each bottle adding
difficulty to the equations.
Bean Bag Toss
Place an enlarged 100 chart on the floor. Using bean bags have student toss the
bean bag and add or subtract the two numbers that the bean bags land on.
What’s the teacher doing?
What are the student’s doing?
Observing and monitoring
Participating as a small group and
demonstrating their understanding of
the concept.
Phase 4 Elaborate on the Concept Day 12
Materials:
Deck of playing cards with numbers 1-10 and Aces (aces = 1)
Game Mat
Addition Equation Cards or Subtraction Equation Cards (one set per pair of
students, laminated if possible)
Activity:
Ace of Number Game Directions, Equation Cards, and Teacher Discussion
Questions
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Unit 5
Addition and Subtraction up to 20
First Grade
Directions:
The object of this game is to be the first to lay down the card that would complete
the problem on the Equation Card.
The dealer shuffles the number cards and deals out 7 to each player.
The dealer then shuffles the equation cards. Player one chooses an Equation
Card and lays it face up in the middle of the table.
The first player to lay down the correct playing card keeps the Equation Card.
If neither player has a card that completes the equation, both players pass and
choose another equation card.
Play continues until one partner has collected 5 Equation Cards.
For example, if the equation is 12 = 10 + _________, the first play to lay down a 2
would keep the Equation Card.
Variation:
Aces are wild cards.
Mix up the cards so students can play both the addition and subtraction version of
the game.
What’s the teacher doing?
What are the students doing?
Monitoring students for understanding.
Working in small groups to understand
addition and subtraction.
Phase 4 Elaborate on the Concept Day 13
Materials:
Deck of playing cards with numbers 1-10 and Aces (aces = 1)
Game Mat
Addition Equation Cards or Subtraction Equation Cards (one set per pair of
students, laminated if possible)
Activity:
Ace of Number Game Directions, Equation Cards, and Teacher Discussion
Questions
Directions:
The object of this game is to be the first to lay down the card that would complete
the problem on the Equation Card.
The dealer shuffles the number cards and deals out 7 to each player.
The dealer then shuffles the equation cards. Player one chooses an Equation
Card and lays it face up in the middle of the table.
The first player to lay down the correct playing card keeps the Equation Card.
If neither player has a card that completes the equation, both players pass and
choose another equation card.
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First Grade
Play continues until one partner has collected 5 Equation Cards.
For example, if the equation is 12 = 10 + _________, the first play to lay down a 2
would keep the Equation Card.
Variation:
Aces are wild cards.
Mix up the cards so students can play both the addition and subtraction version of
the game.
What’s the teacher doing?
What are the students doing?
Observing and monitoring.
Playing the game.
Demonstrating their understanding of the
concept through the game.
Phase 4 Elaborate on the Concept
Materials:
Math Journal
Activity:
Math Journal Activity: Students will write or draw a story problem with an unknown
addend.
Allow time for students to trade their problems with a partner and solve. Students
should be given time to share their strategies and solutions. If needed, students
work in pairs to create the problems and then share with other pairs of students.
Have students use a part whole mat to demonstrate the story problem.
How could the part-part-whole mat be used to model the story problem when
you know one part and the whole? What would you do first? Answers may
vary. I would start by placing 14 counters in the bottom “whole” on the mat; etc.
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First Grade
What’s the teacher doing?
What are the students doing?
Observing and monitoring students
understanding of concept.
Writing and illustrating a story problem
with unknown addend.
Sharing the problems and solution
Phase Five: Evaluate Students’ Understanding of the Concepts Day 15
Materials:
manipulatives
Activity:
Students work to solve each problem of the performance indicator from IFD. (This
should be completed orally as a whole group)
Mathematics Grade 1 Unit 05 PA 01
1) For each problem situation:
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Create a concrete model and record a number sentence to represent and
solve each problem situation.
Orally explain the mathematical relationship between each problem
situation and how each concrete model and number sentence represents
the operation used to solve the problem.
Orally describe the strategies and processes used to solve each problem.
a) Neal had some erasers. His teacher gave him 6 more erasers. Now he has 15
erasers. How many erasers did Neal start with?
b) Neal had 9 erasers. He bought some more from the school store. Now he has
15 erasers. How many erasers did Neal buy?
c) Neal had 9 blue erasers and found 6 more in his desk drawer. How many
erasers does Neal have in all?
2) For each problem situation:
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Create a pictorial model and record a number sentence to represent and
solve each problem situation.
Orally explain the mathematical relationship between each problem
situation and how each pictorial model and number sentence represents the
operation used to solve the problem.
Orally describe the strategies and processes used to solve each problem.
a) Chrissy had 18 roses on her rose bush. She cut 9 of the roses and took them to
her teacher for Teacher Appreciation Day. How many roses are still on the rose
bush?
b) Chrissy bought 18 roses from the plant store. She gave some of the roses to
her mother and now she has 9 roses left. How many roses did Chrissy give to her
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Unit 5
Addition and Subtraction up to 20
First Grade
mother?
c) Chrissy has some roses to sell at the local fair. She has already sold 9 roses
and has 9 more roses left. How many roses did Chrissy have to sell at the local
fair?
3) For each problem situation:
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Create a concrete or pictorial model and record a number sentence to
represent and solve each problem situation.
Orally explain the mathematical relationship between each problem
situation and how each concrete or pictorial model and number sentence
represents the operation used to solve the problem.
Orally describe the strategies and processes used to solve each problem.
a) There are 6 girls and 8 boys on the Yellow Jackets soccer team. How many
players are on the team?
b) Sally saw 8 yellow butterflies and 14 orange butterflies at the park. How many
more orange butterflies did Sally see than yellow butterflies?
c) Peter has black and blue fish in his aquarium. Six of the fish are black. He has 8
more blue fish than black fish. How many of Peter’s fish are blue?
What’s the teacher doing?
What are the students doing?
Monitoring students as they work on the
performance indicator to determine if
any re-teaching is necessary prior to the
unit assessments.
Display understanding of the topics and
skills taught in this unit by completing
the performance indicator.
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