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Common Core MathKindergartenGeometry

K.G.4: Compare Shapes by Sides and Corners

Also written as K.G.B.4 and CCSS.MATH.CONTENT.K.G.B.4 · Cluster: Analyze, compare, create, and compose shapes.

Make a K.G.4 WorksheetAll 22 Kindergarten Math Standards

The Official Wording

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).

Common Core State Standards, Kindergarten, Geometry · Read it at the source · Checked October 14, 2026

What K.G.4 Means in Plain English

Kindergartners put two shapes next to each other and talk about what is the same and what is different. A square and a rectangle both have four sides and four corners, but the square’s sides are all the same length. A triangle has only three corners.

The language is informal: corners rather than vertices, sides rather than edges, the same length rather than congruent. Solids join in too: a cube and a box both have flat faces, a ball has none. In 1st grade these observations become the defining attributes of each shape (1.G.1).

K.G.4 I Can Statements

  • I can count the sides and corners of a shape.
  • I can tell how two shapes are alike and how they differ.
  • I can notice when a shape’s sides are all the same length.

K.G.4 Worked Example

A square and a rectangle compared part by part, which is the conversation this standard wants to hear.

Problem

Here is a square tile and a rectangle tile. How are they the same? How are they different?

Same or different? A square and a rectangle
  1. Count the corners on each, touching every corner once.square: 4 corners, rectangle: 4 corners
  2. Count the sides the same way.square: 4 sides, rectangle: 4 sides
  3. So far they match. Now look at the sides. Are they all the same length?square: all 4 sides the same
  4. Turn the rectangle. Two sides are long and two are short.rectangle: 2 long sides, 2 short sides
  5. Say what is the same and what is different in one breath.same: 4 sides and 4 corners. Different: only the square has all sides equal
AnswerBoth have four sides and four corners. The square’s sides are all the same length, and the rectangle has two long sides and two short ones.

Check it: Lay the square on top of the rectangle with one corner matching. If a strip of rectangle shows past the square, the sides are not all equal.

Common Mistakes with K.G.4

Counting a corner twice

A triangle comes out with 4 or 5 corners because the count restarted

Try this: Put a finger on the first corner and keep it there, then count around with the other hand until you reach that finger.

Same number of sides means the same shape

“They both have four sides, so they are both squares.”

Try this: Ask about the lengths next. Four sides is only the first question, and whether they are all equal is the second.

Comparing color or size instead of parts

“The red one is bigger.” when asked how a triangle and a square differ

Try this: Give two shapes of the same color and size, so the only differences left are sides and corners.

Where K.G.4 Fits

Comes BeforeK.CC.4Count a small set by touching each object once, which is how sides and corners get counted.K.G.2Name a shape in any size or orientation.
AlongsideK.G.3Tell flat shapes from solid shapes.K.MD.2Compare two objects directly to see which is longer.
Comes NextK.G.6Join simple shapes to make a larger shape.1.G.1Separate defining attributes, like three sides, from non-defining ones, like color.2.G.1Recognize and draw shapes with a given number of angles or equal faces.

Practice K.G.4

Math Worksheet GeneratorFree ToolKindergarten shape pages: count the sides and corners of each shape and write the number, then circle the two shapes that have the same count.KindergartenShapesAnswer key
Make a Worksheet
Graph Paper GeneratorFree ToolLarge-square grid paper makes equal sides visible: a square drawn 3 squares on every side, a rectangle 3 by 5. Students count the squares along each side to compare.Large squaresOne page
Make Graph Paper

Quick Check

  1. How many corners does a triangle have? How many does a square have?
  2. A square and a rectangle both have four sides. What is one way they are different?
  3. Mia says a cube and a ball are the same because you can hold both. What is one difference she could name?

K.G.4: Other Names

K.G.4K.G.B.4CCSS.MATH.CONTENT.K.G.B.4

Common Core State Standards © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved. Official wording from the Common Core State Standards PDFs at corestandards.org, last checked October 14, 2026. The explanation, I can statements, example, mistakes and practice on this page are EMStudio’s own, written beside the official wording. They are not part of the standard.