CCSS.Math.Content.5.G.B
The standard
Classify two-dimensional figures into categories based on their properties.
Common Core State Standards for Mathematics
What this standard means
Students need to sort two-dimensional shapes by properties they can observe and name, such as number of sides, angle types, parallel sides, and equal sides. They should use these properties to place shapes into broader and narrower groups, like seeing that every square is also a rectangle and a rhombus.
Mastery looks like students justifying a classification with properties, not appearance. They can explain why a shape belongs in more than one category. Students often get stuck thinking shapes are defined by how they look, or that a tilted square stops being a square.
Ways to teach it
- Give pairs shape cards and have them build a Venn diagram sorting quadrilaterals by parallel sides, equal sides, and right angles.
- Ask students to write: Is every rectangle a parallelogram, and how do you know using properties?
- Show five shapes and ask students to circle all that are rhombuses, then write one property that proves it.
- Have students find logos, tiles, or signs in the room and classify each shape by its geometric properties.
Plan a lesson for CCSS.Math.Content.5.G.B
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Related standards
- CCSS.Math.Content.4.G.A
Draw and identify lines and angles, and classify shapes by properties of their lines and angles.
- CCSS.Math.Content.5.G.B.3
Understand that attributes belonging to a category of two-dimensional figures also belong to all subcategories of that category.
- CCSS.Math.Content.4.G.A.2
Classify two-dimensional figures based on the presence or absence of parallel or perpendicular lines, or the presence or absence of angles of a specified size. ...
- CCSS.Math.Content.5.G.B.4
Classify two-dimensional figures in a hierarchy based on properties.