2G1

[ccoward]

Our standard 2.G.1 says students should be able to identify triangles, quadrilaterals, pentagons, hexagons, and cubes. From reading this I though the students just needed to know that 3 sides = triangle, 4 sides = quadrilateral, etc. In reading the progression description for this standard though, it specifies that they should be able to identify specific categories of quadrilaterals: trapezoids and rhombus. Are they expected to know and be able to pick out those shapes and if so – how do we know that except by reading the progressions (why aren’t they specified in the standard itself?) Is there a list of expected shapes some where?

Also, my colleagues and I have been wondering how much work we should do with 3D shapes. The standard says students need to know about faces, edges, and vertices, but the only 3D shape they need to be able to identify is a cube. Should we go into prisms and other 3D shapes?

Thank you!

[Bill McCallum]

It’s worth quoting the entire text of 2.G.1 here.

Recognize and draw shapes having specified attributes, such as a given number of angles or a given number of equal faces. Identify triangles, quadrilaterals, pentagons, hexagons, and cubes.

The second sentence specifies that the shapes to be recognized and drawn should include the ones listed, but does not limit to those shapes. The core of this standard is the first part of the first sentence: students should have experience recognizing and drawing shapes with specified attributes. The progression gives examples of this that go beyond the list in the second sentence, but should not be interpreted as a required interpretation of this standard. So, basically, this is really up to states to interpret. I would add that the consortium assessments don’t start until Grade 3, so there is really some flexibility here.

[bergba]

Here is the confusion my primary teachers (and myself) are having with attributes of a cylinder.

Sometimes on the cylinder we see that it has 2 faces, 2 edges, and 0 vertices. Other times we see that it is 0 faces, 0 edges, and 0 vertices. We can’t find a clear definition in the standards or anywhere else.

There are mixed messages with how to define a “face” in geometry, therefore,….confusion lies within cylinders!

First question regarding this:
*In 1st grade, students compose two-dimensional shapes or 3-D shapes (including right circular cylinders) to create a composite shape.
*2nd Grade, When we are discussing various attributes in 2.G.1, one of the attributes is the number of faces. However, a cylinder is not mentioned in this specific standard.

Insights? How does CC define faces and attributes of cylinders?
Feeling like I need a better understanding of this progression and the expectations for this topic.

[Anonymous]

I’m a little unclear as to what you are asking here. 1.G.2 mentions cylinders but only to the extent that they might be used to help kids learn to perceive combinations of shapes as a single new shape, or to decompose a combination of shapes into its “original” shapes. I don’t see anything here which hints at attributes, much less attributes of a complicated shape like a cylinder. 1.G.1 is about attributes but only in the sense of defining versus non-defining attributes.

In 2.G.1 we dive a little deeper into those defining attributes from 1.G.2 but I’m thinking that the standard purposefully limits those attributes and shapes to mostly 2D figures and simple attributes like number or sides and number of angles. Including cubes makes sense as an introduction to faces since they are so familiar with the shape. It doesn’t seem to me that cylinders have any place in this standard.

[Bill McCallum]

I think abieniek has answered this as well as I can without further clarification.

[Author]

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