Addition Strategies
That Use Doubles Facts
Objective To provide opportunities for children to explore and
practice doubles-plus-1 and doubles-plus-2 facts.
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Teaching the Lesson
Key Concepts and Skills
• Practice doubles facts. [Operations and Computation Goal 1]
• Develop and practice strategies for addition
that use doubles facts. [Operations and Computation Goal 1]
• Use doubles patterns to practice facts. [Patterns, Functions, and Algebra Goal 1]
Family
Letters
Assessment
Management
Common
Core State
Standards
Ongoing Learning & Practice
1 2
4 3
Playing Domino Top-It
per partnership: 1 set of dominoes
Partners practice addition facts.
Cutting Out Fact Triangles
Math Journal 1, Activity Sheets 1 and 2
scissors 1 envelope per child
Children cut out the first set of 18 Fact
Triangles.
Key Activities
Math Boxes 2 5
Children identify and practice strategies for
facts in which one addend is 1 or 2 more
than the other addend.
Math Journal 1, p. 34
Children practice and maintain skills
through Math Box problems.
Ongoing Assessment:
Recognizing Student Achievement
Use the Math Message. [Operations and Computation Goal 1]
Key Vocabulary
Curriculum
Focal Points
Interactive
Teacher’s
Lesson Guide
Differentiation Options
READINESS
Designing a Doubles Facts Book
pattern blocks Pattern-Block Template paper and pencil
Children explore doubles facts
using a concrete model and create
a Doubles Facts Book.
ENRICHMENT
Exploring Calculator Doubles
Math Masters, p. 30
calculator
Children use calculators to explore the
concept of doubles addition facts.
Home Link 2 5
Math Masters, p. 29
Children practice and maintain skills
through Home Link activities.
doubles-plus-1 facts doubles-plus-2 facts
Materials
Math Journal 1, pp. 27 and 33
Home Link 24
slate paper
Advance Preparation
Before the lesson, draw a unit box on the board and fill it in with a label of your choice. Use the unit box and label
for all the numbers that are not labeled in this lesson.
Teacher’s Reference Manual, Grades 1–3 pp. 195–198
116
Unit 2
Addition and Subtraction Facts
Mathematical Practices
SMP2, SMP5, SMP6, SMP8
Content Standards
Getting Started
2.OA.2, 2.OA.3, 2.NBT.9
Mental Math
and Reflexes
Write all the doubles
addition facts on a sheet of paper.
Pose +9 facts. Encourage children to think +10, then
count back 1. Suggestions:
1 + 9 = ? 10
2 + 9 = ? 11
3 + 9 = ? 12
Math Message
9 + 5 = ? 14
? = 9 + 6 15
? = 7 + 9 16
1 Teaching the Lesson
Math Message Follow-Up
Home Link 2 4
Follow-Up
9 + ? = 16 7
4 + ? = 13 9
? + 9 = 17 8
Review answers as
necessary.
NOTE Remember to reserve time every
WHOLE-CLASS
ACTIVITY
day to complete the number-line, attendance,
calendar, temperature, and weather daily
routines. See Daily Routines on page xxxv of
this book and Teacher’s Reference Manual,
pages 41–49.
(Math Journal 1, p. 27)
Ongoing Assessment:
Recognizing Student Achievement
Math
Message
Use the Math Message to assess children’s knowledge of doubles facts.
Children are making adequate progress if they can correctly record all of
the doubles facts.
[Operations and Computation Goal 1]
NOTE Knowledge of doubles facts is
important as this lesson focuses on strategies
that assume quick recall of these facts. Daily
chanting of the doubles will help reinforce this
skill.
Ask children to turn to the Facts Table on journal page 27. Help
them as needed while they check their list of doubles facts against
the table. Remind children that sums of all doubles facts are even.
Discussing
Student Page
Date
WHOLE-CLASS
ACTIVITY
Doubles-Plus-1 Facts
Doubles-plus-1 facts include those addition facts in which one
addend is 1 more than the other addend (for example, 3 + 2).
Write some doubles-plus-1 facts on the board; leave out the sums.
Use both horizontal and vertical forms. (See page 118.)
Ask children to copy and complete the facts on their slates. See
whether any children mention a strategy that makes use of
doubles. Discuss the doubles-plus-1 strategy. To add numbers
where one addend is 1 more than the other, double the smaller
number and then add 1.
LESSON
Time
23
Addition/Subtraction Facts Table
+,-
0
1
2
3
4
5
6
7
8
9
0
0
1
2
3
4
5
6
7
8
9
1
1
2
3
4
5
6
7
8
9
10
2
2
3
4
5
6
7
8
9
10
11
3
3
4
5
6
7
8
9
10
11
12
4
4
5
6
7
8
9
10
11
12
13
5
5
6
7
8
9
10
11
12
13
14
6
6
7
8
9
10
11
12
13
14
15
7
7
8
9
10
11
12
13
14
15
16
8
8
9
10
11
12
13
14
15
16
17
9
9
10
11
12
13
14
15
16
17
18
Math Journal 1, p. 27
EM3cuG2MJ1_U02_21_52.indd 27
1/7/11 12:31 PM
Lesson 2 5
117
Discussing
WHOLE-CLASS
ACTIVITY
Doubles-Plus-2 Facts
7
+6
4 + 5 =
= 9 + 8
5
+6
Doubles-plus-2 facts are addition facts in which one addend is 2
more than the other addend (for example, 6 + 4). Write some
doubles-plus-2 facts on the board; leave out the sums. Use both
horizontal and vertical forms. (See margin.)
Ask children to copy and complete the facts on their slates. See
whether any children mention a strategy that makes use of
doubles. Discuss doubles-plus-2 strategies. To add numbers where
one addend is 2 more than the other addend, double the smaller
number and add 2.
7
+5
4 + 6 =
= 9 + 7
6
+8
Some children may discover that they can change a doubles-plus-2
fact into a doubles fact by subtracting 1 from the larger addend
and adding 1 to the smaller addend, for example, they might
change 4 + 6 into the doubles fact 5 + 5.
Practicing Addition Strategies
INDEPENDENT
ACTIVITY
That Use Doubles Facts
(Math Journal 1, p. 33)
PROBLEM
PRO
P
RO
R
OBL
BLE
B
LE
L
LEM
EM
SO
S
SOLVING
OL
O
LV
VIN
IN
ING
Children practice and extend the doubles-plus-1 and doubles-plus-2
strategies and extend them to doubles-plus-3 facts.
2 Ongoing Learning & Practice
Playing Domino Top-It
Student Page
Date
Time
LESSON
PARTNER
ACTIVITY
Addition Facts
2 5
䉬
If you know a double, you know the 1-more and the 1-less sums.
Example:
If you know that 4 4 8,
You know
4 5 9,
And
437
1. 3 4 13
3.
7
2. 8 7 67
4.
15
6
5
11
5.
8
9
6.
17
8. 5 8 7
5
7.
9.
Domino Top-It is suggested in anticipation of Lesson 2-6, in which
children use dominoes to construct subtraction facts.
16
12
13
7
9
15
69
10. 8 6 14
Try This
11. 8 8 89
87
13. 15 15 16 15 14 15 16
17
15
30
31
29
12. 12 12 12 13 12 11 14. 14 12 15 13 24
25
23
26
28
Math Journal 1, p. 33
118
Have partners place dominoes face down between them. Each
player turns over a domino and calls out the sum of the dots on
the two halves. The player with the higher sum wins and takes
all the dominoes currently in play.
Unit 2 Addition and Subtraction Facts
Student Page
3
6
4
•
•
ⴚ
ⴙ,
ⴙ,
ⴚ
8
•
7
7•
•
ⴚ
ⴚ
ⴙ,
ⴙ,ⴚ
ⴙ,
3
5
4
2
Home Link 2 5
ⴙ,
ⴚ
2
3
5
(Math Journal 1, p. 34)
Mixed Practice Math Boxes in this lesson are paired with
Math Boxes in Lesson 2-7. The skills in Problems 5 and 6
preview Unit 3 content.
•
8
ⴙ,ⴚ
INDEPENDENT
ACTIVITY
2
2
3
4
6
4
Math Boxes 2 5
2
6
•
ⴙ,ⴚ
Tell children to store the Fact Triangles in envelopes in their tool
kits when they are not using them.
These Fact Triangles will be used in Lessons 2-7 and 2-11
through 2-13 as addition and subtraction flashcards. In Lesson
2-12, children will cut out a second set of Fact Triangles from
Activity Sheets 3 and 4.
8
ⴚ
ⴙ,
Have children cut out the Fact Triangles from Activity Sheets 1
and 2. You might want to have them write their initials or draw a
distinctive pattern on the back of each triangle. This will help
children identify their individual sets.
•
4
2 5
•
ⴙ, ⴚ Fact Triangles 1
䉬
2
(Math Journal 1, Activity Sheets 1 and 2)
Time
LESSON
3
INDEPENDENT
ACTIVITY
5
Cutting Out Fact Triangles
Date
h
Math Journal 1, Activity Sheet 1
INDEPENDENT
ACTIVITY
(Math Masters, p. 29)
Home Connection Children complete a page of addition
facts and draw a path from the child to the ice-cream cone
by connecting sums of 9, 10, or 11.
Student Page
Date
Home Link Master
Name
Time
LESSON
2 5
䉬
Math Boxes
䉬
2. Circle the activity that takes
your math journal? Fill in the
circle next to the best answer.
rhombus
B
rectangle
about 1 second.
Reading a story.
C triangle
D square
Family
Note
Help the child find the ice-cream cone. Answer all the problems.
Then draw the child’s path by connecting facts with sums of 9,
10, or 11. You can move up, down, left, or right as you move
between boxes.
2
6
2
5
1
6
0
8
5
7
3
9
7
0
4
4
1
5
4
3
2
7
6
5
1
7
3
5
6
3
1
8
8
2
5
3
2
4
3
3
8
7
4
4
5
4
9
3
0
9
4
6
7
1
5
5
8
0
5
9
6
7
6
1
6
2
3
8
7
4
9
2
5
3
4
4
2
9
4
8
4
9
1
1
5
2
3
4
6
6
8
4
7
5
7
0
6
2
7
3
3
6
4
7
6
8
5
6
8
5
3
6
4
7
5
2
1
6
3
5
6
7
5
7
8
3
7
7
9
4
6
1
8
4
2
6
7
7
4
2
1
4
0
7
3
9
4
5
6
4
52
3. Complete the fact family. Fill in
the missing domino dots.
8
7
7
7
15
8 15
15 8
8 15 7
25
5. Put the numbers in order from
4. How likely is it that our school
will have a fire drill today?
Circle your answer.
9
certain
Answers vary.
likely
8
unlikely
impossible
6. Draw hands to show 8:15.
smallest to largest. Circle the
middle number.
11
10
48, 44, 37, 54, 39
12
2
3
9
37 , 39 , 44 , 48 , 54
46
Math Journal 1, p. 34
8
4
7
6
5
8
7
1
For homework, your child will review addition facts like the ones we have been working on
in class. To help identify the path from the child to the ice-cream cone, have your child circle
the sums of 9, 10, and 11.
Please return this Home Link to school tomorrow.
Blinking your eyes.
Writing your name.
Time
Addition Facts Maze
25
1. What shape is the cover of
A
Date
HOME LINK
13
8
11
7
8
9 12
7
8
12 12 12
7 12
9
9 10
11 11 11
9 11
8 12 12
7
8 14
8
7
7
6
9 10
8 10
7
8
8
6
6
6 15
8 14 13
8 11 12 13
8 10
7
2
7
7
9 11 14 11
8 13 12 11 14 13
5
7 12
9 10
Math Masters, p. 29
Lesson 2 5
119
Teaching Master
Name
Date
LESSON
Time
3 Differentiation Options
Calculator Doubles
25
䉬
You can program the calculator to solve doubles problems.
1. First clear your calculator.
2. Enter
,
,
,
. (The calculator will display a 4).
Do NOT clear your calculator again while you work on this page.
3. Guess what the sum is for double 6 (6 + 6).
4. Now enter
and press
5. Guess what the sum is for double 9 (9 + 9).
6. Now enter
and press
12
. What does the calculator display?
12
18
. What does the calculator display?
18
READINESS
Designing a Doubles
INDEPENDENT
ACTIVITY
15–30 Min
Facts Book
7. Make up your own doubles problems for the calculator to
solve. Record your number sentence and the sum the
calculator displays.
Example:
Sample answers:
7 7 14
8 8 16
6 6 12
5 5 10
Try This
8. Why do you think you entered
on the calculator to
program it to solve doubles problems?
Sample answer: I think each X shows 2 more
times. So you keep adding the given number
that many times.
Math Masters, p. 30
To explore doubles facts using a concrete model, have
children design a Doubles Facts Book using their
Pattern-Block Template. First, have children create a
doubles fact using pattern blocks of the same shape. Next,
children copy the design onto a sheet of paper using their
template. Each design shows a doubles fact accompanied by a
number model. Staple the pages together to create a Doubles
Facts Book. In addition to having children describe their “double”
designs using color and shape words, have them identify the sum
as odd or even. For example, “There are three sides on each green
triangle. I have two green triangles. Three plus three equals six.
There are six sides in my design. Six is an even number.” “There
are two red trapezoids and two yellow hexagons. Two plus two
equals four. There are four shapes in my design. Four is an even
number.” Ask children what they notice about the sums of the
doubles facts. Sample answer: They are even. Have a volunteer
explain why the sums of doubles facts are even. Sample answer:
When 2 even numbers or 2 odd numbers are added together, the
sum is always even because you will always have pairs.
ENRICHMENT
Exploring Calculator Doubles
PARTNER
ACTIVITY
5–15 Min
(Math Masters, p. 30)
To further explore the concept of doubles addition facts, have
children work with a partner to solve “doubles” problems on
a calculator.
120
Unit 2 Addition and Subtraction Facts