Symmetry is an important concept in math, science and art. When objects have line symmetry, the two halves of the item are identical and will match exactly if you fold the object in half. The concept of symmetry is an integral geometric concept that lays the foundation for later geometric theorems.

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## Symmetry Sort

For this game, you will need 10 shapes with line symmetry and 10 shapes without symmetry. Die cut shapes, such as gingerbread men, are great for showing symmetry. Give each pair of students a set of shapes. The object is to correctly sort the shapes into those with symmetry and those without. Give each group two to three minutes to sort their shapes. When time is up, the groups that have sorted their shapes correctly receive a sticker or other small prize. Sets of printable shapes are available online.

## Symmetry Matching

Print out or draw a set of symmetrical shapes and cut them in half along their lines of symmetry to make symmetrically matching cards. Have the cards laminated to use in the future. Have each student choose a partner for this game. Provide each pair of students with a set of symmetrically matching cards. Students mix up the cards and lay them face down on the table or floor. Students take turns flipping over two cards to see if they are mirror images of each other. If a student finds a "match," she can keep the cards. If she does not find a "match," she must turn both cards face down. Play continues until all the matches have been found. The student with the most cards wins. You can find printable symmetrical shapes on the Internet.

## Symmetry Race

Draw a 4-by-4 grid on a sheet of flip-chart paper. Create a pattern with circles, squares, triangles and blank spaces. Make smaller grids for students to use at their seats with foam shapes. In the first round, have students copy the pattern exactly. Set a timer, and offer prizes to all students who match the pattern. Erasers, pencils and other small prizes are appropriate. You may wish to offer a special prize to the first correct finisher, to make the game more competitive. In the second round, have students make a mirror image of the first pattern. In subsequent rounds, challenge students to rotate the pattern at various angles.

## Symmetry Guess-the-Grid

Have each student create an 8-by-8 square grid on graph paper. Each column of the grid is labelled with a number, 1 through 8. The rows are labelled with letters A through H. Each student creates a symmetrical pattern in the grid by colouring some squares. Students should be careful not to let anyone else see the pattern. Each student must choose a partner to play the game. Game play is similar to "battleship." Students take turns guessing squares they think may be part of their opponent's pattern. The first student to guess all his opponent's coloured squares wins.