Identify the figure that does not fit the classification rule - CogAT Grades K 2

SECTION 1

Why Do We Sort Things Into Groups?

People have always loved to sort things! Think about how you sort your toys. You might put all the cars together and all the dolls together. Sorting means putting things that are alike into groups. When we sort, we also notice which things do not belong in a group.

Long Ago • People Sorted Food

Long ago, people sorted plants into groups: ones you can eat, and ones you cannot eat. This helped keep them safe!

1900s • Teachers Made Puzzles

Teachers started making picture puzzles to see how well kids could think about shapes and groups.

1950s • The CogAT Test Was Created

Smart test-makers created the CogAT test. It has fun puzzles where you look at shapes and find the one that does not fit!

Today • Kids Take CogAT

Today, kids like you take the CogAT. You use your eyes and brain to figure out which picture does not belong.

So how do you figure out which shape is the odd one out? That is what this lesson will teach you!

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Important Ideas to Know

Before we start, let's learn some important ideas. These ideas will help you find the figure that does not fit every time.

What Is a Rule?

A rule tells us what makes shapes the same. For example, "all circles" is a rule.

Look at Shape

Is it a circle, square, triangle, or something else? Shape is one thing that can make a figure different.

Look at Size

Is one figure big and the others small? Size can be a clue that one does not fit.

Look at Color or Shading

Is one figure dark and the rest are light? Color and shading can help you find the one that is different.

Look at Number of Sides

Count the sides! If most shapes have 4 sides but one has 3, the one with 3 sides does not fit the number-of-sides rule.

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KEY TAKEAWAY

Think about sorting your crayons. If you have a box of red crayons and one blue crayon is hiding inside, the blue crayon does not fit! It is the same with shapes on the test. Most of them share something — your job is to find the one that is different.

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See It in a Picture

Let's look at a picture to understand! Below, you will see five shapes. Four of them are alike. One is different. Can you spot which one does not belong?

Shapes A, B, and D are all circles. Shape C is a square. The square does not fit because it has a different shape.

Did you notice? Three shapes were circles, and one was a square. The rule here is "all circles." The square breaks that rule, so it does not belong!

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How to Think Step by Step

Here is a simple way to solve these puzzles. Think of it like being a detective! You look for clues. Follow these steps every time.

Your Detective Steps

Step 1: Look at ALL the figures first. Do not rush!
Step 2: Ask yourself: What do MOST of them have in common?
Step 3: Check shape, size, color, shading, and number of sides.
Step 4: Find the one figure that is NOT like the others.
Step 5: Double-check! Make sure the other figures really do match.

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Helpful Tip!

Sometimes the rule is tricky! It might not be about shape. It could be about size, shading, or even which way a shape is pointing. Always check more than one thing!

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Different Kinds of Rules

The figures on the CogAT test can follow many different rules. Let's look at the most common ones so you will be ready for anything!

This picture shows five different kinds of rules: shape, size, shading, direction, and number of sides. The red figure in each row is the one that does not fit.

Now you know five big clues to look for. When you see a puzzle, try checking each of these clues one at a time. The one that makes most figures match is probably the rule!

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Let's Solve One Together

Let's pretend you see four shapes on a test. Three are big dark triangles pointing up. One is a big dark triangle pointing down. Let's work through our detective steps!

Finding the Figure That Does Not Fit

1
Step 1 — Look at All the Figures

We see four triangles. They are all big and dark. They all look very similar at first!
2
Step 2 — Check Shape

All four are triangles. Shape is the same for everyone. So the rule is NOT about shape.

Shape: All the same ✓
3
Step 3 — Check Size

All four are big. Size is the same for everyone. So the rule is NOT about size.

Size: All the same ✓
4
Step 4 — Check Shading

All four are dark. Shading is the same for everyone. So the rule is NOT about shading.

Shading: All the same ✓
5
Step 5 — Check Direction

Three triangles point UP. One triangle points DOWN. We found the difference! The one pointing down does not fit the rule "all triangles point up."

Answer: The triangle pointing down does not fit!

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Great Job!

See how we checked each clue one at a time? Sometimes you need to look at shape, size, shading, AND direction before you find the answer. Be patient like a detective!

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What Works and What Is Tricky

Some puzzles are easy and some are hard. Let's look at what makes things easier and what can be tricky.

What Helps You	What Can Trick You
Looking at ALL the shapes before picking	Picking the first shape that looks a little different
Checking shape, size, color, and direction	Only checking one thing like color
Looking for what MOST shapes share	Getting confused when two things are a little different
Taking your time and double-checking	Rushing through the puzzle

Helpful hints and common mistakes

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KEY TAKEAWAY

Think of it like a game of "One of These Things Is Not Like the Others." In that game, you look at a group and find the one that is different. On the CogAT, you do the same thing, but with shapes! The trick is to look at everything about each shape, not just one thing.

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Getting Ready for Harder Puzzles

As you grow and learn more, the puzzles will get harder. But don't worry! The same detective steps will always help you. Let's see how easy puzzles and harder puzzles are different.

Easier Puzzles (Now)	Harder Puzzles (Later)
Simple shapes like circles and squares	Shapes inside other shapes
One rule to find (like shape)	Two or more rules at once (like shape AND size)
Clear differences between figures	Small, tricky differences
Solid or empty shapes	Shapes with stripes, dots, or patterns

How puzzles change as you get older

The more you practice now, the better you will be at the harder puzzles later. Think of it like learning to ride a bike. First you use training wheels, then you ride all by yourself!

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Practice Problems

Now it is your turn! Read each question carefully. Think about what the shapes have in common. Then find the one that does not fit.

Question 1: CONCEPTUAL

You see four shapes: a red circle, a red square, a red triangle, and a blue circle. Which one does not fit if the rule is about color?

Show answer

The blue circle does not fit. The rule is "all shapes are red." Three shapes are red, but the blue circle is not red. Even though it is also a circle, the rule here is about color, not shape. So the blue circle is the odd one out.

Question 2: BASIC CALCULATION

You see five shapes: four big squares and one small square. Which one does not fit?

Show answer

The small square does not fit. All five shapes are squares, so the rule is not about shape. But four squares are big and one is small. The rule is about size. The small square breaks the rule "all squares are big," so it is the one that does not belong.

Question 3: INTERMEDIATE

You see four triangles. Three are pointing up and are filled in with dark color. One is pointing up but is empty (not filled in). Which one does not fit, and what is the rule?

Show answer

The empty triangle does not fit. All four shapes are triangles and all point up, so the rule is not about shape or direction. The difference is shading. Three triangles are filled in (dark), and one is empty (white inside). The rule is "all triangles are filled in." The empty triangle breaks this rule.

Question 4: APPLIED

You see five figures: a big dark circle, a big dark square, a big dark triangle, a big dark star, and a small light diamond. Which one does not fit? Be careful — there might be more than one thing different!

Show answer

The small light diamond does not fit. The other four shapes are all big and dark. The diamond is both small AND light. Even though each shape has a different form (circle, square, triangle, star), they all share two things: being big and being dark. The diamond breaks both of these rules, making it clearly the odd one out.

Question 5: CRITICAL THINKING

You see four figures. Three are circles with a small dot inside them. One is a circle with no dot inside. Another student says the answer is wrong because "they are all circles, so they all fit." Why is the other student not correct?

Show answer

The other student is only looking at the outside shape. Yes, all four are circles. But the rule is about what is inside the circle. Three circles have a dot inside, and one does not. The rule is "all circles have a dot inside." The circle without a dot does not fit. This shows us that we need to look at everything about a figure, not just its outside shape. Details inside the shape matter too!

SUMMARY

Let's Remember What We Learned

Summary

On the CogAT Nonverbal Battery, you will see a group of figures. Most of them follow a classification rule — they share something in common. Your job is to find the one figure that does not fit the rule. To do this, check shape, size, shading, direction, and number of sides.

Remember to use your detective steps: look at all the figures, ask what most of them share, check each clue, find the different one, and then double-check your answer. Take your time, be patient, and you will do great!