# Shape Sort

 1 2 3 3 1 2 2 3 1
Latin and Euler squares are great puzzles, similar to the now popular Sudoko puzzles. In a Latin square, you place a given set of n objects into a n x n grid in such a way that no two similar objects fall in the same row or column. For example, to the left is a 3 x 3 grid with three different numbers arranged as a Latin square.
 1 2 3 3 1 2 2 3 1
An Euler square has the same number of objects in the same size grid, but this time the objects have an extra characteristic, for instance, color. So now the set contains the numbers 1, 2, and 3 but each number comes in three different colors (total of nine items to place). To the left is the same arrangement but now neither number NOR color is repeated in the same row or column.Additional grids that are 4×4 or larger can be used with the accompanying number of n2 items in one or two characteristics.
This activity can be played with color tiles, which come in four colors (red, yellow, blue, green). Draw a 4×4 grid with the squares the same size as the color tiles. Give the children a bag of sixteen color tiles (four each color). Tell them to place the tiles on the grid so no color is repeated in any row or column. How many different solutions can they find?
This activity can be played with younger children as a Latin square with numbers, letters, pictures, or geometric shapes. Or older children can solve the puzzle with two characteristics. I use large posterboard cutouts of geometric shapes in different colors. These can be placed into a huge grid taped or chalked onto the playground or cafeteria floor.

# Birthday Cards

 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 2 3 6 7 10 11 14 15 18 19 22 23 26 27 30 31 4 5 6 7 12 13 14 15 20 21 22 23 28 29 30 31 8 9 10 11 12 13 14 15 24 25 26 27 28 29 30 31 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

With the five cards above, you can guess anyone’s birthday!

 Make the five separate cards by writing the numbers on a 3×5 card. Give the five cards to your friend, and ask them to hand you the cards that contain the number date of their birthday. You secretly and quickly add up the first number on each of the cards your friend hands back to you. The sum is their birthday date — in base two! Remember that base two counts whether or not you need the place values 1, 2, 4, 8, 16, 32, etc to sum up the number. By picking the cards, your friend has indicated that the place value at the top of those cards will have a face value of one. The cards they did not pick are those that will have a face value of zero. Practice with a partner until you can find your answer quickly. Then surprise all your friends!

# Guess the Volume

 Find a large jar and fill it with candy, marbles, blocks, or whatever. Challenge the children and parents to figure out how many items are in the jar. This is measuring volume using non-standard measurement. Have each person write their guess on a slip of paper and put it in a box. At the end of the night, sort through the guesses and find the person who is closest to the correct number of items. They may win a prize or the contents of the jar. A good strategy for this problem is counting how many items are on the bottom layer of the jar. Then count how many “layers” of these items are up and down the jar. Multiply the number of items on the bottom (area of the base) with the number of layers (height) to get the volume.

# Symmetrical Butterfly Cards

Symmetrical Butterfly Birthday Card
See more activities in: Kindergarten, Birthdays

There is nothing quite as pleasing to the eye as the sight of symmetry. Make bilateral symmetry even more engaging to your child by incorporating it into this beautiful butterfly birthday card! Your child will be enchanted with her ability to paint a brilliant butterfly made up of perfectly even shapes, and the recipient of this card will be just as delighted! This fantastic introduction to symmetry will also stimulate her creativity and fine motor skills.

### What You Need:

• White cardstock paper (8 1/2″ x 11″)
• Colored construction paper (preferably slightly bigger than the white paper)
• Tempera or poster paints
• Felt-tip pens
• Glue

### What You Do:

1. Fold the white paper in half and ask your child to paint two large blobs, one on top of the other on one side of the fold, so that it looks like one half of a flying butterfly. The paint must be applied quite thickly so that it transfers successfully to the other half of the paper.
2. Encourage her to quickly put some drips of contrasting paint on the blobs.
3. Have her carefully fold the paper along the fold, whilst the paint is still wet, pressing down on it from the outside edge of the paper to the fold.
4. Ask her to carefully unfold the paper; the image should now look like a butterfly!
5. Whilst the paint is drying, fold the construction paper in half.
6. Get your child to write a birthday message on the front of the construction paper card (with the fold on the left).
7. Once the painting has dried, ask your child to use more paint and felt tip pens to add details such as antennae and a body. Encourage her to try and keep the image symmetrical.
8. Glue the folded butterfly painting inside the construction paper card.
9. The recipient will be greeted with a surprise butterfly when she opens the card!

Variations:

Invite your child to make a cluster of symmetrical butterfly pictures and cut them out. When they are dry, punch holes on the tops and hang them on a length of ribbon as a decoration.

If you want to take this activity a step further and help develop your child’s spatial skills, you can play the following game: Get your child to think about shapes that are symmetrical (hearts, circles, squares etc.). Fold another piece of paper in half and paint half of one of the shapes that your child has suggested with paint. To check her answer, ask her to fold the paper over and press down to make a print.

# Mathdoku

### Overview

KENKEN is Sodoku with Math

Think of Kenken as Mathdoku. It’s an arithmetic and logic puzzle (like sudoku), except that to produce a certain target number you need to combine numbers using a specified mathematical operation.

### Rules

• For a 3×3 puzzle, fill in with numbers 1-3
• For a 4×4 puzzle, fill in with numbers 1-4
• For a 5×5 puzzle, fill in with numbers 1-5
• For a 6×6 puzzle, fill in with numbers 1-6
• For a 7×7 puzzle, fill in with numbers 1-7
• For a 8×8 puzzle, fill in with numbers 1-8
• For a 9×9 puzzle, fill in with numbers 1-9
• Do not repeat a number in any row or column
• The numbers in each heavily outlined set of squares, called cages,
must combine (in any order) to produce the target number in the top
corner of the cage using the mathematical operation indicated.
• Cages with just one box should be filled in with the target number
in the top corner.
• A number can be repeated within a cage as long as it is
not in the same row or column.

## What You’ll Need

Sample Completed Kenken board

• Understanding of how to do the mathematical operations
like adding, subtracting, multiplication, and division.

### How To

• First go through and fill in the single boxes.
• Then fill in the rows or columns with the least amount of open boxes.

### Why You Should Try This

• Helps you understand and be able to do math better.

### Where’s the Math?

This activity addresses the following Texas Essential Knowledge Standards :

• (3.3.b) select addition or subtraction using the operation to solve problems involving whole numbers through 999.
• (3.4.a) learn and apply multiplication facts through 12 by 12 using concrete models and objects.

# Envelope Tetrahedron

 A tetrahedron is a 3-D geometrical figure with four faces. It yields the smallest volume for its surface area. A tetrahedron is one of the Platonic Solids.
 Turn a small envelope into a triangular pyramid

Simple Q’s

Count the sides
Count the corners
Count the edges

Trace sides to show    they are the same    size/shape

 Make a Tetrahedron from a Small Envelope Regular Polyhedra

This is a simple way to make a tetrahedron(a pyramid) from a small envelope. All you need is a small envelope, a ruler, a pencil and scissors.

Supplies:

• Small envelope (a business-sized envelope will NOT work)
• Pencil
• Ruler
• Scissors

Instructions:

 Open the flap of a small envelope. Using a ruler and a pencil, mark the diagonal lines from each corner to the opposite corner. Mark a third vertical line through the middle of the envelope. Fold along each of the lines.

 Open up the envelope, flattening the bottom a bit. Tuck one side of the envelope into the other side.

 You now have a tetrahedron! To decorate it: untuck it, draw on the sides (but not on the tucked-in side), then re-tuck one side in.

Moderate Q’s

Congruent angles,    edges, faces
Count the vertices
Triangula

 Cut along the top two “V”-shaped lines (discard the top of the envelope).

r base

Complex Q’s

Find the surface    area
Find the volume

Explore other    polyhedrons