5.G.B.4 Classify Shapes with Tangrams

5.G.B.3  Understand that attributes belonging to a category of two-dimensional figures also belong to all subcategories of that category. For example, all rectangles have four right angles and squares are rectangles, so all squares have four right angles.

5.G.B.4  Classify two-dimensional figures in a hierarchy based on properties.





Using exactly 3 tangram blocks to form each shape, we investigated quadrilaterals and other polygons.

Patricio was excited to add interesting details to his polygons. So artistic!

During classroom discussions, the children began to ask questions to clarify their thinking about the various quadrilateral shapes, so we started researching some of the terms:

The children knew the definition of a rectangle for sure, so we started there.

Next, we looked at quadrilaterals that did not have 4 right angles.






If all 4 sides are equal, it is a rhombus.


We also had a long discussion about baseball diamonds. I told them that diamond is not a math term.  A baseball diamond is a square that is just rotated with home base on one of the vertices.

It's going to take a while for some of the children to believe me on that one!

The students noticed that a square is a rhombus, a parallelogram, a quadrilateral, and a rectangle.


But square is a unique and highly specialized term. Only a square has 4 right angles and 4 equal sides.









After classifying the shapes, I made these diagrams to help them visualize the concepts.

More Tangram Puzzles

 The next day, everyone continued building other tangram shapes.

Jorge made a hexagon and Patricio decorated his polygons with patriotic colors from Mexico.










The children had a delightful afternoon trying to solve tangram puzzles or creating imaginative shapes of their own with the blocks.

Tangram website

Plus more virtual manipulatives from the National Library of Virtual Manipulatives.

Mom and Me Math with Tangrams

Tangram puzzles work well for Family Math Night, too.

The children always love to present their solutions to the entire class.

Thank you to all of our mothers for your wonderful support!!  We love having you share the math lesson with us in school.

Good job presenting to the class, Dionsá.     Mom is very proud of you!  :)