AB and ABC Patterns

For Elementary Students

What is a Pattern?

A pattern is something that repeats over and over in the same way.

Think about it like this: Patterns are like a song with a beat that keeps repeating — you can predict what comes next!

What is an AB Pattern?

An AB pattern uses two things that repeat: A, then B, then A, then B, and so on.

Example with colors:

Red, Blue, Red, Blue, Red, Blue...

🔴 🔵 🔴 🔵 🔴 🔵

A = Red, B = Blue

The pattern repeats: AB AB AB

Example with shapes:

Circle, Square, Circle, Square, Circle, Square...

⭕ ▢ ⭕ ▢ ⭕ ▢

A = Circle, B = Square

Example with numbers:

1, 2, 1, 2, 1, 2...

A = 1, B = 2

What is an ABC Pattern?

An ABC pattern uses three things that repeat: A, then B, then C, then A, then B, then C...

Example with colors:

Red, Yellow, Blue, Red, Yellow, Blue...

🔴 🟡 🔵 🔴 🟡 🔵

A = Red, B = Yellow, C = Blue

The pattern repeats: ABC ABC

Example with shapes:

Star, Heart, Triangle, Star, Heart, Triangle...

⭐ ❤️ 🔺 ⭐ ❤️ 🔺

A = Star, B = Heart, C = Triangle

Other Patterns

AAB Pattern:

Red, Red, Blue, Red, Red, Blue...

🔴 🔴 🔵 🔴 🔴 🔵

ABB Pattern:

Circle, Square, Square, Circle, Square, Square...

⭕ ▢ ▢ ⭕ ▢ ▢

AABB Pattern:

1, 1, 2, 2, 1, 1, 2, 2...

Extending a Pattern

Extending means continuing the pattern — figuring out what comes next.

Example: Red, Blue, Red, Blue, Red, ___

What comes next? Blue! (The pattern is AB, so after Red comes Blue.)

Example: Star, Star, Moon, Star, Star, Moon, Star, ___

What comes next? Star! (The pattern is AAB: Star, Star, Moon repeats.)

For Junior High Students

Identifying the Core Unit

The core (or unit) of a pattern is the part that repeats.

Example: 🔴 🔵 🟢 🔴 🔵 🟢 🔴 🔵 🟢

Core: 🔴 🔵 🟢 (ABC pattern)

Once you identify the core, you can predict any position in the pattern!

Describing Patterns

You can describe patterns using letters:

Patterns with Numbers

Example: 3, 7, 3, 7, 3, 7...

Pattern type: AB

Core: 3, 7

Next three numbers: 3, 7, 3

Example: 10, 10, 20, 10, 10, 20...

Pattern type: AAB

Core: 10, 10, 20

Next three numbers: 10, 10, 20

Finding a Specific Position

Question: In the pattern 🔴 🔵 🟢 🔴 🔵 🟢..., what is the 10th item?

Step 1: Identify the core Core = 🔴 🔵 🟢 (3 items)

Step 2: Divide the position by the core length 10 ÷ 3 = 3 remainder 1

Step 3: The remainder tells you which item in the core

• Remainder 1 → 1st item in core = 🔴
• Remainder 2 → 2nd item in core = 🔵
• Remainder 0 → last item in core = 🟢

Answer: The 10th item is 🔴 (Red)

Creating Your Own Patterns

Steps:

1. Choose your elements (colors, shapes, numbers, letters)
2. Decide the pattern type (AB, ABC, AAB, etc.)
3. Repeat the core at least 3 times so the pattern is clear

Example: Create an ABB pattern with animals

🐶 🐱 🐱 🐶 🐱 🐱 🐶 🐱 🐱

Core: Dog, Cat, Cat

Real-Life Patterns

Clothing: Striped shirt (white, black, white, black) = AB pattern

Tiles: Floor pattern (square, circle, square, circle) = AB pattern

Music: Drum beat (boom, tap, tap, boom, tap, tap) = ABB pattern

Calendar: Days of week repeat (7-element pattern)

Traffic lights: Red, Yellow, Green, repeat = ABC pattern

Patterns vs. Sequences

Pattern: Repeats the same core over and over

Sequence: May follow a rule but doesn't necessarily repeat (we'll learn about growing sequences later)

Pattern: 2, 4, 2, 4, 2, 4 (repeats AB)

Sequence: 2, 4, 6, 8, 10 (adds 2 each time, doesn't repeat)

Practice