The Greedy Triangle

The Greedy Triangle

By: Lauren Nixon

Mathematics/Geometry

2nd grade

Lesson# 1 of 10

Total Time Allotted: 60 minutes

GOALS

1: Geometry

Recognize and draw shapes having specified attributes, such as a given number of           angles or a given number of equal faces. (Sizes are compared directly or visually, not           compared by measuring.) Identify triangles, quadrilaterals, pentagons, hexagons, and             cubes. (2.G.1 Common Core Goals)

4: Literacy

Use words and phrases acquired through conversations, reading and being read to, and responding to text, including using adjectives and adverbs to describe (e.g., When other         kids are happy that makes me happy). (2.L.6 Common Core Goals)

 OBJECTIVES

1.1   Following a lesson on the number of angles and sides particular shapes have,            students will identify and draw triangles, quadrilaterals, pentagons, and hexagons on    their two-dimensional shapes chart, 5 out of 6 times.

4.1   After listening to The Greedy Triangle and a lesson on sides and angles of plane       shapes, students will use the vocabulary words: hexagon, pentagon, quadrilateral, and        triangle, to name shapes on their two-dimensional shapes chart, 5 out of 6 times.

PRE-REQUISITE KNOWLEDGE

Student will need to know what a shape is and be familiar with common shape names such as triangle, square, and rectangle. This lesson will also require students to know how to write.

MATERIALS/EQUIPMENT/ SUPPLIES/ TECHNOLOGY/PREPATION

• The Greedy Triangle, by: Marilyn Burns
• Chart paper
• White board
• Pre-cut triangles with varied shapes and sizes (50)
• White paper
• Glue
• Scissors
• Crayons
• Pencil
• Pattern blocks
• Shapes Book, page 1-2

                                                                     Procedure

	Teacher does …	Students do …
Time10 min.	Anticipatory set The instructor calls the class to the carpet and introduces the story, The Greedy Triangle. The instructor then reads the story and asks critical thinking questions throughout the text such as what the students predict the next shape will be. When new shapes names are mentioned in the book the instructor writes them on the board with the number of sides next to it.	Anticipatory set Students listen to the story, while answering questions, making observations and predications.
20 min.	Teaching After reading the story, the instructor directs the students’ attention to the list of words from the book. “Here is another new word. All of these shapes are also called polygons. Even though they have different numbers of sides, they all have straight sides. And they all enclose a space, the way a fence does.” The teacher talks with the students about prefixes, asking them what other words they can think of that begin with these prefixes and explaining what those words mean. “The triangle asked for a new side and angle. Can someone point to what is a side of a triangle? Can someone point to an angle?” The teacher explains to the class that over the next few weeks they will be working on geometry. Geometry is explained as a branch or mathematics that looks at the different characteristics or attributes of shapes. The instructor also explains that throughout their geometry unit they will be looking at flat shapes called two-dimensional shapes. Other times they will be using solid objects like the Geoblocks, called three-dimensional shapes.	Teaching Students brainstorm words that begin with the prefixes. The students demonstrate their comprehension of what a side and angle is on a shape, by pointing to them on different shapes. The students listen to directions for their individual time.
20-25 min.	Independent Application The instructor shows the class the cut triangles and explains that they will each choose one triangle and think about what your triangle might be a part of. The instructor explains “When you have an idea glue your triangle down onto your white piece of paper and draw a picture around it. Then write a sentence to describe your picture.” The instructor also explains that once they have finished with their artwork, they will work on page 1 and of their Geometry folder. The teacher explains that the students will look at pattern blocks and write the name, number of sides and angles, and draw a picture of it.	Independent Application Students look at their triangle and decide what it could be a part of. The student then glues down their triangle and draws a picture around it. The last part of this activity is for them to write a sentence to explain their picture. The student must incorporate the word triangle within the sentence. Students then work at their desks on their two-dimensional chart in their Geometry folder. The students look at pattern blocks and analyze the shape by its number of sides and angles. The student decides what the name of the shape is and records the information in the chart, along with a picture.
5 min.	Closure The teacher shares the completed pictures and explains that geometry is a part of the world all around them.	Closure The students look at their peers pictures and add to the discussion of how geometry is a part of the world all around them.