Clements, D. Investigations in Number, Data, and

Space: Picturing Polygons. Dale Seymour, 1998.

Proposed Time Frame:

Picturing

Polygons

2-D Geometry

Unit Goals:

•

Reasoning and communicating about

properties of geometric shapes

•

Sorting and classifying triangles and

quadrilaterals

•

Estimating and measuring the size of

angles and turns

Materials:

◊

Deck of Guess My Rule Cards

◊

Two areas for grouping shapes according to

whether or not they fit a rule - for example,

a circle made of string or two different

pieces of paper.

Procedure:

1. The first player chooses a rule and gives a

few examples, putting those shapes that fit

the rule in one place and those shapes that

do not in the other place. The rule should

focus on properties of geometric shapes.

2. The second player tries to guess the rule by

placing a shape either inside or outside the

circle, depending on whether the player

thinks it fits the rule or not.

3. The first player says whether or not the

placement is correct.

4. The second player uses this information to

eliminate possibilities, devise new solutions,

and revise earlier guesses of what the rule

might be. Using this new information, the

second player again tries to guess where a

particular shape belongs.

5. Repeat steps 3 and 4. The second player can

guess a rule if the player thinks he or she has

found a solution. The first player says

whether or not the rule is correct.

6. Play continues until the second player guesses

the rule or there are no shapes left to place.

Math Game

Investigations in

Schools

Web Resources

You will find web resources at:

http://www.everett.k12.wa.us/math

www.illuminations.nctm.org - select

Activities

http://www.rainforestmaths.com/

Ask your teacher for the password

to download the Geo-Logo software

for Picturing Polygons

.

Glossary

polygon —

a plane shape having three or

more sides

quadrilateral

— a polygon with four

sides.

coordinates

— used to show position on

a grid; shown as pairs of letters or num-

bers, e.g. (8,4)

On-Line Glossary

http://www.amathsdictionaryforkids.com/

Guess My Rule: Shapes

---

Listed below are questions to

Getting Started

∗

What is it that you don’t under-

stand? (Have your child be spe-

cific.)

∗

What do you need to find out?

∗

What do you need to know?

∗

What terms do you understand

or not understand?

While Working

∗

How can you organize the infor-

mation?

∗

Do you see any patterns or re-

lationships that will help solve

this?

∗

What would happen if…?

Reflecting about the Solution

∗

How do you know your answer

is reasonable?

∗

Has the question been an-

swered?

∗

Can you explain it another

way?

At Home:

As the unit unfolds, your child will work

with:

∗

Polygons with different numbers of

sides, from 3 up to 10.

∗

Polygons whose angles and sides

follow certain rules.

∗

Regular polygons (with all sides

equal).

When your child has assignments to

work on at home, talk about them

together and participate when asked. For

example, how does your child find and

draw a polygon that is “hidden” on a

coordinate grid? When you and your

child try to draw angles of a certain

number of degrees - without any tools,

just estimating - how close can both of

you come? Is a square a rectangle? Is a

retangle a square? What are the rules for

these polygons?

Look for opportunities to talk about

shapes and angles with your child. Most

of the angles in our rooms and on our

furniture are right angles (90º angles).

Why is this? Equilateral triangles have

60º angles. Diagonal across a square

forms a 45º angle. If your child has any

game boards or spinners, look at their

designs. Do you see any of these

angles? What other angles do you see?

Above all, see how much fun shapes can

be, and enjoy watching the growth of

your child’s understanding of geometry.

Clements, D. Investigations in Number, Data, and

Space: Picturing Polygons. Dale Seymour, 1998.

Mathematics in

Investigations

Investigation 1:

∗

Distinguishing between polygons and shapes

that are not polygons

∗

Drawing polygons

∗

Locating points on a coordinate grid

∗

Using the Geo-Logo commands

setxy

and

jumpto

to draw polygons on the computer

∗

Recognizing and naming polygons by number

of sides

Investigation 2:

∗

Reasoning and communicating about proper-

ties of geometric shapes

∗

Sorting and classifying triangles and quadri-

laterals

∗

Developing vocabulary to describe special

triangles and quadrilaterals

∗

Generating geometric figures from descrip-

tions of their properties

∗

Estimating and measuring the size of angles

and turns

Polygons

Non-

polygons