# K.G.B.4

Analyze and compare two- and three-dimensional shapes, in different sizes and orientations, using informal language to describe their similarities, differences, parts (e.g., number of sides and vertices/“corners”) and other attributes (e.g., having sides of equal length).

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## Summary:

Students should be pushed to describe differences and similarities between shapes by using the language referenced in the standard as opposed to just any wording. For instance, children should be encouraged to move past statements like "It has flat sides and is pointy" to more specific statements like "It has 3 sides and 3 corners".

## Understanding the Standard:

• Students need opportunities to sort shapes and objects based on attributes such as size and number, and other attributes such as number of corners or having sides of equal length.
• Attributes of shapes can be those that are meaningful for kindergartners, such as whether objects can be stacked or whether they roll.
• Students need practice identifying how shapes are alike and different, as well as comparing shapes and describing their similarities and differences.
• Students need exposure to “non-traditional” examples of rectangles and triangles, such as obtuse triangles or long, skinny, tilted rectangles.
• Students will use informal language to describe shapes and should be encouraged to progress to more appropriate math language as understanding increases.
• Teachers can ask students to sort shapes in a second way, and show visible excitement when they sort shapes according to defining attributes like number of sides.

## Specific Questions to Focus Instruction:

• Are students able to describe the attributes of both two-dimensional (flat) and three-dimensional (solid) shapes? At this age, they may use informal language like sides and corners rather than higher math terms like edges and vertices.
• Are students able to pick out all the shapes with three sides in a group?
• Does the student give justification for how he/she knows that an object is indeed a particular shape? For example, "it is a square because all the sides are the same".
• Can students sort objects by attributes, and can they describe why they sorted them the way they did?
• Can students identify attributes of solid shapes, such as whether they can be stacked, and whether they can roll?
• Are students able to discuss the differences and similarities amongst a group of shapes and sort them accordingly?

## Skills

Prior to: Some students continue to identify a shape by its appearance, and sometimes use the language of two-dimensional shapes to describe three-dimensional shapes.

At Grade Level: Given a variety of two-and three-dimensional shapes in different sizes and orientations, students can analyze and compare, using informal language to describe their similarities, differences, parts, and other attributes. For example, students can compare an equilateral triangle and a long, skinny, obtuse triangle, explaining that they both have three sides.

Moving Beyond:
Students will use proper terminology to describe two-and three-dimensional shapes, and how they compare.