Math Investigations

Help with Opening PDF Files

Chapter 15

Part 1: For the activity in the Teacher's Edition, page 412

Provide students with a copy of the Activity Page (PDF file).

Bring in magazines, and have the students bring in magazines. Have the students look through the magazines to find pictures of geometric shapes. Have them outline the figures they find with colored markers. Have them share with each other what they have found, being sure to talk about the number of sides of the shapes in the discussion. You might want to set up a bulletin board in your classroom with areas for three-sided figures, four-sided figures, etc.

Check the magazine pictures and the students' outlines.

Part 2: Be an Investigator

A good time to do this investigation is after Lesson 2 on classifying plane figures.


  • crayons

Data Sheet


The minimum number of colors needed to color a face of the Louvre pyramid, with no common edges sharing the same color, is two.

The minimum number of colors needed to color a face of the abstract drawing, with no common edges sharing the same color, is four.

Introducing the Investigation

Introduce the investigation by reading aloud the assignment at the top of the first page of the Description of Investigation and Student Report (PDF file), by having one of your students read aloud the assignment, or by having the students read the assignment individually.

Put students in groups of 2 to 4 students to work on the investigation.

Doing the Investigation

Make sure that students understand what "no common edges share the same color" means. Draw some figures on a paper and illustrate with markers cases where common edges share the same color and cases where common edges do not share the same color.

Student Report

The student report gives the students an opportunity to show what they have done.

Extending the Investigation

The students can try this activity with other designs and see how many colors they need so that no common edges share the same color.

Houghton Mifflin Math Grade 3