points and line segments - everyday math · children define and name points and line segments with...
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322 Unit 5 3-D and 2-D Shapes
Advance Preparation
Teacher’s Reference Manual, Grades 1–3 pp. 131, 132
Key Concepts and Skills• Solve number stories using addition facts.
[Operations and Computation Goal 1]
• Connect points in a sequence to draw
line segments.
[Geometry Goal 1]
• Use a straightedge to draw a line segment.
[Geometry Goal 1]
Key ActivitiesChildren define and name points and line
segments with letter labels. They also
practice drawing line segments with a
straightedge according to a code.
Ongoing Assessment: Recognizing Student Achievement Use an Exit Slip (Math Masters, page 415). [Geometry Goal 1]
Key Vocabularypoint � straightedge � line segment �
endpoint
MaterialsMath Journal 1, p. 113
My Reference Book, p. 50
Home Link 5�1
Math Masters, p. 415
straightedge
Practicing with +, – Fact Triangles +, – Fact Triangles
Children practice addition and
subtraction facts using Fact Triangles.
Math Boxes 5�2Math Journal 1, p. 114
Children practice and maintain skills
through Math Box problems.
Home Link 5�2Math Masters, p. 127
Children practice and maintain skills
through Home Link activities.
READINESS
Making Geoboard DesignsMath Masters, p. 128
geoboard � rubber bands
Children use a geoboard to explore making
designs with line segments.
ENRICHMENTCreating a Line Segment DesignMath Masters, p. 129
straightedge � crayons
Children explore drawing line segments in
a sequence.
Teaching the Lesson Ongoing Learning & Practice Differentiation Options
Points andLine Segments
Objective To guide children as they define, name, and draw
line segments.
Ol
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eToolkitePresentations Interactive Teacher’s
Lesson Guide
Algorithms Practice
EM FactsWorkshop Game™
AssessmentManagement
Family Letters
CurriculumFocal Points
Common Core State Standards
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Links to the Future
Lesson 5�2 323
•
•
••
B •
A •
D •E •
1 Teaching the Lesson
� Math Message Follow-Up WHOLE-CLASSDISCUSSION
Write a few of the children’s sentences on the board. If interest in this activity is high, add a few sentences of your own. For example:
� My pencil has a sharp point.
� The football team scored 21 points.
� This number has a decimal point in it.
� Can you point out the picture you like the best?
Discuss the meaning of the word point in geometry—an exact location in space, the tiniest part of a figure, an object without length, something represented by a dot, and so on.
� Discussing How Points WHOLE-CLASS ACTIVITY
Are NamedDraw five dots on the board. Ask someone to choose one of the dots and to tell you which one it is without pointing to it. He or she will probably have a hard time doing this.
Explain that an easy way to talk about points is to give them labels. Points are usually labeled with capital letters, such as A, B, and C. Label each of the dots on the board, calling them by name as you do so: “Point A,” “Point B,” and so on.
This is a preliminary exposure to drawing and labeling points. Identifying and
drawing points are Grade 3 Goals.
Getting Started
Math Message Write a sentence that has the word point or points in it.
Home Link 5�1 Follow-Up Review the rule and write it on the board. Ask volunteers to draw shapes that fit that rule.
Mental Math and ReflexesPose number stories with “harder” addition and subtraction facts:
Alexi has 8 toy cars. Theo has 7 toy cars. How many do they have in all? 15 toy cars
Jillian had 9 crayons. She found 6 more. How many crayons in all? 15 crayons
Shantell brought 14 lollipops to school. She gave away 8 during lunch. How many does she have now? 6 lollipops
Maya went down the slide 17 times during recess. Jason went down 9 times. Maya went down the slide how many more times than Jason? 8 times
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324 Unit 5 3-D and 2-D Shapes
Math Journal 1, p. 113
Student Page
NOTE There is a difference between a
straightedge and a ruler. A straightedge is a
tool for drawing straight lines. A ruler is both
a measuring and a drawing tool. A ruler is a
straightedge, but a straightedge may or may
not be a ruler, depending on whether it is
divided into unit intervals. This distinction
need not be made for children at this time.
Drawing a line segment labeled AB
Adjusting the Activity
Consider posting point, straightedge, line
segment, and endpoint on the Word Wall so children can refer to them as necessary. Include a picture and a written description from the glossary next to each word.
AUDITORY � KINESTHETIC � TACTILE � VISUAL
ELL
� Defining and Naming WHOLE-CLASS ACTIVITY
Line Segments(Math Masters, p. 415; My Reference Book, p. 50)
Ask children what they think straight means. “Not curved” or “goes in one direction” are good responses. Point out that a straightedge is a tool used for drawing straight lines.
On blank sheets of paper, have children draw two dots as you do the same on the board. Label the dots A and B. Then demonstrate how to draw a “straight line” connecting them: Place the straightedge just under the dots and draw from point to point, not from letter to letter, and not past the points. Tell children that they just drew a line segment whose endpoints are points A and B. The segment can be called “line segment AB” or “line segment BA”—the names of the endpoints can be in either order. Write
_ AB
and _
BA on the board and say that sometimes the symbols are used for “line segment AB” or “line segment BA.” For a summary of these concepts, read My Reference Book, page 50 with your class.
Ask children to draw three points (that are not in a straight line) on their papers and to label each point with a different letter. Explain that in any problem or example, all the points must have different names; two points may not have the same letter label. Have children use a straightedge to connect each of the three points to each of the other points. Ask children to name the shape they have formed. A triangle
Ongoing Assessment: Exit Slip
Recognizing Student Achievement
Use an Exit Slip (Math Masters, page 415) to assess children’s ability to use a
straightedge to draw a line segment. Have children use a straightedge to draw
line segment EF. Children are making adequate progress if they are able to use
the straightedge to draw a line segment. Some children may indicate the
endpoints and still others may label the endpoints.
[Geometry Goal 1]
� Drawing Line Segments PARTNER ACTIVITY
with a Straightedge(Math Journal 1, p. 113)
The first part of the journal page shows points connected by line segments, along with a code that specifies the sequence in which the points have been connected. For example, the code A→B→C→A means: “First draw a line segment from A to B, then a line segment from B to C, and finally one from C to A.” Give partners 2 or 3 minutes to figure out the codes. Then go over the three codes with the class.
In the second part of the activity, children draw line segments according to given codes. Partners can work on these problems while you circulate and assist children who need help.
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Lesson 5�2 325
Name Date Time
In this lesson, your child learned to name points and line segments with capital letters. Using a straightedge, your child drew line segments to create shapes. Provide your child with a ruler, a piece of stiff cardboard, or another object having a straight edge. Observe as your child draws line segments. Ask your child to name the shapes that he or she draws in Problems 1 and 2 below (a 6-pointed star and a hexagon).
Please return this Home Link to school tomorrow.
Family Note
HOME LINK
5 �2 Line Segments
1. Draw these line segments: 2. Draw these line segments:
3. Draw the following line segments:
How many triangles are
there? 6
4. Draw points on the back of this page. Label each point with a letter. Use a straightedge to connect the points with line segments to make polygons.
Practice
5. 23 + 20 = 436. 14 + 30 = 447. 45 + 30 = 75
FAEFDECDBCAB A
B F
E DCDFBDBFEACEAC A
B F
E DC
BEAD,EF,CD,AB,
FCFADEBC B
A C
DEF
Use a straightedge to draw line segments.
50
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Math Masters, p. 127
Home Link Master
Math BoxesLESSON
5 �2
Date Time
1. Fill in the missing numbers.
3. Which number is an odd number less than 50?Circle the best answer.
A 50
B 37
C 26
D 55
6. 12 red jelly beans. 16 green jelly beans. How many more greenjelly beans?
2.
How many more books did Alex read in December than in September?
4. Solve.
8 + 6 =
Write the turn-around fact.
5. What time is it?
: In 15 minutes
it will be
: .
50
125
Rule
�25
Key: = 1 book
Alex’s Reading LogDecemberNovember
OctoberSeptember
Books Read
Unit
12 12
3
4567
8
9
1011
Quantity
Quantity
Difference
16
12
Fill in the diagram and write a number model.
97 22
110 111
?
6 + 8 = 14
16 - 12 = 4
14
42
2
30
45
25 75
100
5
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Math Journal 1, p. 114
Student Page
2 Ongoing Learning & Practice
� Practicing with +, - Fact TrianglesHave children practice addition and subtraction facts using their Fact Triangles. As children practice, ask them to sort the Fact Triangles into two piles—facts they know from memory and facts that need more practice. Have them write down the facts for which they need practice.
� Math Boxes 5�2 INDEPENDENTACTIVITY
(Math Journal 1, p. 114)
Mixed Practice Math Boxes in this lesson are paired with Math Boxes in Lesson 5-4. The skill in Problem 6 previews Unit 6 content.
� Home Link 5�2 INDEPENDENTACTIVITY
(Math Masters, p. 127)
Home Connection Children connect 6 points with line segments in different ways to form a 6-pointed star and a hexagon. Children connect other line segments andanswer a question about the shapes that are formed.
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326 Unit 5 3-D and 2-D Shapes
gg
Use a straightedge and a crayon.
Connect the dots below according to the following pattern:A →B→C →D →E→F→A
What shape did you make with line segments? Use a different color. Connect the dots again in a different way. Follow this pattern:A→C→E→A
What shape did you make with line segments? Use a different color. Connect the dots one more time. Follow this pattern:B→D→F→B
What shapes do you see in your design? Color your design.
LESSON
5 �2
Name Date Time
A Line Segment Design
A
D
F B
E C
Sample answers: hexagons, triangles, star, rectangles
hexagon
triangle
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Math Masters, p. 129
Teaching Master
LESSON
5 �2
Name Date Time
Geoboard Designs
1. Use 3 rubber bands to make a design. Record your design.
3. Use 8 rubber bands to make a design. Record your design.
Answers vary.
2. Use 6 rubber bands to make a design. Record your design.
4. Make up your own. I used rubber bands to
make a design. Record your design.
Math Masters, p. 128
Teaching Master
3 Differentiation Options
READINESS INDEPENDENTACTIVITY
� Making Geoboard Designs 5–15 Min
(Math Masters, p. 128)
To explore drawing line segments, have children use rubber bands to make designs on a geoboard. The rubber bands can only be used with a row or column of pins enclosed, so that children are making designs from line segments. (See margin.) They can make shapes or simple designs with intersecting or parallel line segments. This should be an exploration with line segments—not an introduction to them. When children are satisfied which each design, they use a straightedge to record their designs on Math Masters, page 128.
ENRICHMENT INDEPENDENTACTIVITY
� Creating a Line 5–15 Min
Segment Design(Math Masters, p. 129)
To explore using line segments in a design, have children follow directions for drawing line segments in a sequence. As children complete Math Masters, page 129, they should recognize some of the shapes that they draw. Have children describe the process for drawing the shapes. Encourage the use of vocabulary such as point, line segment, endpoint, connect, and shape names.
Planning Ahead
In preparation for the Shapes Museum that will be introduced in Lesson 5-6, collect a few objects or pictures of objects having the following shapes:
Cylinders: coffee cans, rolls of paper towels, rolls of toilet paper, drinking straws, mugs, fluorescent lightbulbs
Spheres: tennis balls, oranges, globes
Rectangular prisms: books, cereal boxes, cartons, chalkboard erasers, pictures of a file cabinet, pictures of a bookcase
Cones: ice cream cones, party hats, conical paper cups, pictures of traffic cones
Pyramids: pictures of pyramids or pyramid-shaped roofs
Cubes: notepaper cubes, regular dice, centimeter cubes, a liter (cubic decimeter) box
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