The Greedy Triangle

The Greedy Triangle

Posted By: Alexandra Acocella

Title: The Greedy Triangle

Author: Marilyn Burns

Illustrator: Gordon Silveria

Awards: A Marilyn Burns Brainy Day Book

Recommended Grade Level: Grades 2-4

Common Core Standards Addressed:

CCSS.MATH.CONTENT.2.G.A.1  Recognize and draw shapes having specified attributes, such as a given number of angles or a given number of equal faces.1 Identify triangles, quadrilaterals, pentagons, hexagons, and cubes.

CCSS.MATH.CONTENT.4.G.A.1  Draw points, lines, line segments, rays, angles (right, acute, obtuse), and perpendicular and parallel lines. Identify these in two-dimensional figures.

CCSS.MATH.CONTENT.4.G.A.2  Classify two-dimensional figures based on the presence or absence of parallel or perpendicular lines, or the presence or absence of angles of a specified size. Recognize right triangles as a category, and identify right triangles.

CCSS.MATH.PRACTICE.MP7     Look for and make use of structure.

Mathematically proficient students look closely to discern a pattern or structure. Young students, for example, might notice that three and seven more is the same amount as seven and three more, or they may sort a collection of shapes according to how many sides the shapes have. Later, students will see 7 × 8 equals the well remembered 7 × 5 + 7 × 3, in preparation for learning about the distributive property. In the expression x2 + 9x + 14, older students can see the 14 as 2 × 7 and the 9 as 2 + 7. They recognize the significance of an existing line in a geometric figure and can use the strategy of drawing an auxiliary line for solving problems. They also can step back for an overview and shift perspective. They can see complicated things, such as some algebraic expressions, as single objects or as being composed of several objects. For example, they can see 5 - 3(x - y)2 as 5 minus a positive number times a square and use that to realize that its value cannot be more than 5 for any real numbers x and y.

Summary: This book is about a triangle who grows tired of having only three angles, therefore visits a shapeshifter who adds another angle to him, thus becoming a quadrilateral.  Becoming greedy, the now quadrilateral grows weary and continues to visit the shapeshifter who adds additional angles until he can’t add any more.  The book expresses examples of how each shape could exist in the world because shapes are all around us, if we would only take the time to look.

Rating: ***** 5 Stars!- This book deserves five stars not only for the content but the way that it is presented.  Geometry is a hard enough topic as it is for students and having to memorize names of shapes is not any easier.  The Greedy Triangle presents the information in a way that is both amusing to kids but also easy to remember.  Students will be able to recall where they have seen a particular shape in the world and therefore remember how many angles or sides the shape has.  This book gives the students real world connections.  In addition to math, a teacher would be able to tie in many other topics such as friendship and social studies.  The illustrator did a fabulous job of bringing Burns’ story to life so that kids would stay engaged. Overall I would use this book in my classroom to teach a lesson!

Classroom Ideas: This book can be used in a lesson to teach geometry, specifically shapes.  This text would be a good way to start introducing different types of shapes, therefore reinforcing new vocabulary/material.  In the beginning of a lesson you could have students do a walk through around your classroom and find specific shapes. You could also have a homework assignment where students are asked to bring in cut out pictures of everyday items in these same specific shapes and categorize them. For a lesson you could have students actually make a three-dimensional triangle and then continually add angles just like in the story.  In addition to math, a teacher could also tie in the theme of friendship, social studies, and even English.  You could have students write a first person narrative on why they are unhappy being a specific shape.  You could tie in any mathematical lesson on the attributes of triangles, quadrilaterals, or any other geometric shape.  This book has a lot of different possible angles where teachers would be able to develop various lessons based on their objective.