I taught third grade for 14 years in both public and private schools. The curriculum always included many geometry objectives. Here are some tips on how to teach geometry at home:
1. Relate geometry to the real world. Share how geometry is all around us. It is in nature and the real world. Discuss how the sun, a plant’s leaf, or a starfish show symmetry. Share pictures of Turkish buildings to show how geometric principles are used in the tilework on the floor and walls. Show how artists like M.C. Escher use geometry in their artwork to create illusion and tessellations. Pop art is a neat way to share examples of how geometry is used to plays tricks on the eye. Also, explain how geometry has words for things we can only imagine and they help us talk about the world we live in, such as congruent, symmetry, points, lines, and angles. Get your child excited about geometry!
2. Buy a geoboard to use with rubber bands. You could make this if you like by getting a piece of square wood and nailing in 20+ small nails with 5-10 in each row to hang the rubber bands from each nail. Have your child make polygons and name them. For instance, have them make a quadrilateral, a pentagon, a hexagon, a heptagon, an octagon, a nonagon, a decagon, and more by using the rubber band(s) on the nail pegs. Ask them how many sides and angles each polygon has. What do they notice?
3. Buy mini marshmallows and toothpicks. Have your child construct three-dimensional shapes (i.e. cube, rectangular prism, triangular prism, cylinder) and have them use math language to describe their figure, such as how many lines, vertices, and angles are there. What types of angles do they see? It is easy to insert a toothpick in each end and use the marshmallows as the glue between the toothpicks.
4. Use grid paper to not only relate perimeter and area with multiplication, but the little squares can be used to create an optical illusion art piece. Check out this lesson. Discuss the meaning of transformations – flip, slide, and turn and have your child illustrate examples on the grid paper.
5. Play Concentration with Angles. On small blank cards, write 4 right angles, 4 obtuse angles (any size angle), and 4 acute angles (any size angle). Mix the cards up and have them put the cards face down. Each player flips two cards over, identifies the angle, and if they are a match, they keep the cards. If they are not a match, the cards are flipped back over. Players take turns until there are no cards left. The player with the most cards at the end wins.
6. Use old magazines and let your child find as many example of symmetry as possible. When something is symmetrical it has a line of symmetry and one side is a mirror image of the other. Objects can have more than one line of symmetry. Use grid paper and draw one shape on one side of a line of symmetry and have your child draw the other mirror reflection.
7. Shapes – After a mini review/lesson on name of two-dimensional and three-dimensional shapes and angles, have your child search your house or point to real world shapes and name them – cylinder (soup can), sphere (globe), cube, rectangular prism (TV, cereal box), square pyramid, etc.
8. Have your child show you on their fingers the following: parallel lines, intersecting lines, and perpendicular lines. Ask them to describe the differences.
10. Check out these great sites to refresh your geometry vocabulary knowledge and have your child practice online: