Download Greedy Triangle

Name: Leta Roberts
Topic: 2 Dimensional Shapes - The Greedy Triangle - Using Reading to Help Teach
Mathematics
Grade Level/Subject: 2nd/Mathematics
State Competency (P.A.S.S.): Standard 4.1.b. – Identify two-dimensional geometric
shapes in everyday situations (e.g., a stop sign is an octagon).
Description: Students will listen to the story The Shape of Things by Dayle Ann Dodds
and make a foldable. To introduce students to shapes in the real world they will view the
video Discovering Math from Discovery Education. Students will listen to The Greedy
Triangle by Marilyn Burns, use geoboards to create various polygons, and make a
foldable.
Time Required for Lesson: 5 days/ 45 minutes each
Goals:
1. Students will be able to recognize and identify various polygons.
2. Students will be able to identify properties of polygons with the use of pictures
from newspapers, magazines, and pictures from the internet.
3. Students will review geometric terms by making predictions about how the
triangle changes in the book.
4. Students will make the connection that a polygon's name refers to the number of
sides that it has.
Objectives: Students will be able to:
1. Recognize the following geometric shapes: triangle, quadrilateral, parallelogram,
trapezoid, rectangle, square, rhombus, pentagon, hexagon, heptagon, octagon,
nonagon, and decagon.
2. Relate each shape's name to its number of sides.
3. Construct the geometric shapes on a geoboard.
4. Construct geometric shapes out of construction paper.
5. Learn to write a summary of their work.
6. Makes foldables to help retain concepts learned.
Materials and resources:
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document camera or overhead projector
clear geoboard for the overhead
geoboards for students
rubber bands
pictures of shapes
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The Greedy Triangle by Marilyn Burns
Computer & Smartboard for video and games
construction paper
scissors
markers
Vocabulary:
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two-dimensional – shapes that have length and width
circle – a round shape with no sides or corners
polygon – a closed, flat shape that has a least 3 straight sides
angles – the space between two straight lines with a common endpoint
vertex – the point where the rays of an angle meet
triangle -- a polygon with 3 sides and 3 angles
parallelogram – a four sided figure in which both pairs of opposite sides are
parallel and equal
8. trapezoid – a four sided figure with one pair of sides parallel and the other pair not
parallel
9. rectangle – a quadrilateral with two pairs of equal and parallel sides and four right
angles
10. square – a quadrilateral with four equal sides and four right angles
11. rhombus – a parallelogram with four equal sides
12. quadrilateral -- a polygon with 4 sides and 4 angles
13. pentagon -- a polygon with 5 sides and 5 angles
14. hexagon -- a polygon with 6 sides and 6 angles
15. heptagon – a polygon with 7 sides and 7 angles
16. octagon – a polygon with 8 sides and 8 angles
17. nonagon -- 9-sided polygon
18. decagon -- 10-sided polygon
Introduction:
Day 1: Read the story The Shape of Things. Discuss what a polygon is and make a
foldable for the definition of two-dimensional shapes (include circle, square, triangle,
rectangle, and parallelogram)..
Day 2: Using the SmartBoard review polygons including quadrilaterals, squares,
rectangles, triangles, parallelograms, and trapezoids. View the video Discovery Math
and make a foldable for the quadrilateral shapes (include parallelogram, trapezoid,
rectangle, square, and rhombus).
Day 3: Review what the sides, vertex, and angles are. Hold up pictures of a triangle,
quadrilateral, pentagon, hexagon, heptagon, octagon, nonagon, and decagon and ask if
anyone can identify the shapes. Ask where students may have seen these shapes in their
environment (at school, at home, at the store, on the road or sidewalk, etc.). Have the
students listen to the story, The Greedy Triangle. Tell the students they are to make
predictions about what the triangle becomes as you read the book. Also, tell the students
to think about the theme of the book and be able to explain it. Instruct the students to
listen for the names of the different shapes mentioned in the story. Review the words on
the vocabulary list. [Summary of Story: A triangle is bored with having only three
sides, so he goes to the shape doctor. He is changed into a quadrilateral, pentagon,
hexagon, heptagon, octagon, nonagon, and decagon. The book goes through the
characteristics of each shape. Finally he decides that being a triangle is the best.]
After the story is read, ask students to share the shapes that were mentioned in the book.
Make the foldable for the number name shapes.
Day 4 & 5: Spend these days on learning center activities. Some suggestions: Matching
shapes to real world pictures; Draw shapes and labeling them using geometry templates;
Geoboard – making the matching shape on their boards; Anglelegs – make the shapes
(the kids love this one); Laminated worksheets with dry erase markers – included in
worksheets from math.about.com; Web-based game on SmartBoard; Polygon information
web site (this is a great resource and can be shown on the SmartBoard) Polygon information web site.url
Instructional Process:
Ask, "Do you remember yesterday we talked briefly about how we name shapes? Can
anyone tell me what we said?" Explain to students that you name a shape by the number
of sides the shape has (a hexagon has 6 sides, a nonagon has 9 sides, etc.). Review the
prefixes and their meanings (hex- means 6, pent- means 5, etc.). Distribute one geoboard
and a few rubber bands (different colors if available) to each student. (If you don't have
enough geoboards for all students, then you can have students work in pairs.) On the
document camera or overhead use a geoboard to model how to form each shape. Students
should make the same shapes on their geoboards that you are making on the overhead
geoboard. Give students 5-10 minutes to experiment making shapes on their geoboards.
Have students pair up to discuss and compare the shapes that they made. Have students
make a foldable for these shapes.
Closure:
Discuss, as a group, what the names of the shapes are and how they have gotten their
names. Have the students write a short entry in their math journals about naming and
identifying geometric shapes. Set up learning centers (examples included) to allow
students access during the week. The remainder of the week can be spent taking turns at
each center.
Assessment: When students are using the geoboards, assess the following: Are students
following the directions? Do their shapes look the way they are supposed to? Can
students identify and name the shapes? Did students name their shapes correctly? Does
each shape have the correct number of sides?
Modifications/Accommodations: 1. As students hold up their geoboards to show the
shapes they have made, check for any student having trouble and give individual help to
those students. 2. Take a walk to look for shapes in the real world. To help children
keep track of their ideas, make a small blank book by cutting plain paper in half and
stapling several sheets together. Have the children draw what they see and write what
and where it was. 3. Do an art activity. Cut out an assortment of polygons in several
colors. Have students choose one and think about what it might be a part of. Glue the
shape to a piece of drawing paper and draw a picture around it.
Technology: Video - Discovering Math: Geometry from Discovery Education http://player.discoveryeducation.com/index.cfm?guidAssetId=15CB0362-1024-41F48DC3-731073306891&blnFromSearch=1&productcode=US; Teacher’s Guide http://gtm-media.discoveryeducation.com/videos/27392/7BC26A07-1279-3B00CD344617F2875DE8.pdf; Worksheets - http://gtmmedia.discoveryeducation.com/videos/27392/7F8CD369-ADCD-C7F468CB9CD4B079E432.pdf Web Game - http://www.ixl.com/math/practice/grade-2identify-planar-and-solid-shapes
Reflection: The book, The Greedy Triangle, engages the children and stimulates their
imaginations. It encourages them to develop a love of books and reading while also
learning about math. The students really enjoy all the hands-on activities which give
them the opportunity to make the shapes and name the shapes. I felt like the foldables
were great reinforcements for what we had discussed as a class. These will be saved in
their math folders for future reference.