NY Next Generation Math NY-3.G.1

Math3rd GradeReason with shapes and their attributes.

The Standard

Recognize and classify polygons based on the number of sides and vertices (triangles, quadrilaterals, pentagons, and hexagons). Identify shapes that do not belong to one of the given subcategories.

New York State Next Generation Mathematics Learning Standards

Teacher's field guide

What This Standard Means

What Students Need to Do: Students classify polygons by counting sides and matching vertices, including triangles, quadrilaterals, pentagons, and hexagons. They also identify polygons and non-polygons outside those named groups.
What Mastery Looks Like: A student names a five-sided polygon as a pentagon even when its sides are unequal or it is rotated. The student can explain why an eight-sided polygon is not one of the four named subcategories.
Common Misconceptions: Students may classify by overall appearance instead of counting sides and vertices. They may think every quadrilateral is a square, reject irregular polygons, or miscount a vertex where two sides meet.
How to Assess It: Give the student a set of varied figures to classify, including one polygon outside the four named groups and one non-polygon. Ask for reasons.

Lesson moves

Ways to Teach It

Build polygons with sticks and clay vertices, then sort them by matching counts of sides and vertices.
Ask students whether every four-sided polygon is a square and have them use examples to support the answer.
Play polygon mystery by revealing clues about side and vertex counts until partners name or draw a matching category.
Survey tile, sign, and package shapes, then record each polygon's side count and category in a class chart.

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