Number Patterns and Sequences

Mathematics

Class 5 | CBSE, NCERT & ICSE

Learning Objectives

Introduction — Patterns Are Everywhere!

Look around you — patterns are everywhere! The petals of a flower, the stripes on a tiger, the tiles on a floor, the rhythm of music, and even the way numbers behave. In mathematics, a pattern is a set of numbers or shapes that follow a definite rule.

A sequence is a list of numbers written in a specific order, where each number follows a rule. For example: 2, 4, 6, 8, 10, ... — can you see the pattern? Each number is 2 more than the previous one. Finding patterns helps us predict what comes next, and this skill is used in science, computer programming, music, and art!

Image needed: A collage showing patterns in nature and maths — sunflower spirals, Rangoli geometric patterns, number sequences on a chalkboard, and a peacock feather. Connecting nature to maths.
Style: Collage-style illustration, vibrant colours, Indian elements (Rangoli, peacock)
Size: 700Ɨ400px

Types of Number Patterns

1. Arithmetic Patterns (Add or Subtract a Constant)

In an arithmetic pattern, you add (or subtract) the same number each time. This constant is called the common difference.

PatternRuleCommon DifferenceNext 3 Terms
5, 10, 15, 20, ...Add 5+525, 30, 35
3, 7, 11, 15, ...Add 4+419, 23, 27
100, 92, 84, 76, ...Subtract 8āˆ’868, 60, 52
1.5, 3.0, 4.5, 6.0, ...Add 1.5+1.57.5, 9.0, 10.5

Example 1: Find the next 3 terms: 7, 12, 17, 22, ...

Solution: Common difference = 12 āˆ’ 7 = 5 (adding 5 each time)

Next terms: 22 + 5 = 27, 27 + 5 = 32, 32 + 5 = 37

Answer: 7, 12, 17, 22, 27, 32, 37

Example 2: Find the rule and the missing number: 95, 86, 77, ___, 59, 50

Solution: Difference = 86 āˆ’ 95 = āˆ’9 (subtracting 9 each time)

Missing number = 77 āˆ’ 9 = 68

2. Geometric Patterns (Multiply or Divide by a Constant)

In a geometric pattern, you multiply (or divide) by the same number each time. This constant is called the common ratio.

PatternRuleCommon RatioNext 3 Terms
2, 6, 18, 54, ...Multiply by 3Ɨ3162, 486, 1458
5, 10, 20, 40, ...Multiply by 2Ɨ280, 160, 320
10000, 1000, 100, 10, ...Divide by 10Ć·101, 0.1, 0.01
3, 12, 48, 192, ...Multiply by 4Ɨ4768, 3072, 12288

Example 3: Find the next 2 terms: 4, 12, 36, 108, ...

Solution: 12 Ć· 4 = 3, 36 Ć· 12 = 3, 108 Ć· 36 = 3 → Common ratio = Ɨ3

Next: 108 Ɨ 3 = 324, 324 Ɨ 3 = 972

Answer: ..., 108, 324, 972

3. Repeating Patterns

A group of numbers repeats over and over.

Example 4: 1, 4, 9, 1, 4, 9, 1, 4, 9, ...

The group {1, 4, 9} repeats. The 10th term = 1 (start of 4th cycle).

Special Number Sequences

Square Numbers

A square number is the result of multiplying a number by itself: n Ɨ n = n²

n12345678910
n²149162536496481100

Pattern in square numbers: The difference between consecutive squares is always odd: 4āˆ’1=3, 9āˆ’4=5, 16āˆ’9=7, 25āˆ’16=9, ... (differences: 3, 5, 7, 9, 11, ...)

Triangular Numbers

Triangular numbers count dots arranged in triangles: 1, 3, 6, 10, 15, 21, 28, ...

Rule: Add 2, then 3, then 4, then 5, ... (add one more each time)

Position1st2nd3rd4th5th6th7th8th
Number1361015212836
How11+21+2+31+2+3+41+2+3+4+5+6+7+8
Image needed: Visual representation of triangular numbers using dots arranged in triangles — showing 1 dot, 3 dots (triangle), 6 dots (bigger triangle), 10 dots, 15 dots. Each triangle clearly labelled with its number.
Style: Colourful dot diagrams, clean and educational
Size: 650Ɨ300px

Cube Numbers

A cube number is n Ɨ n Ɨ n = n³. They represent the volume of cubes.

n123456
n³182764125216

The Fibonacci Sequence

One of the most famous patterns in mathematics! Each number is the sum of the two numbers before it:

0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, ...

Rule: Next term = Previous two terms added together

Did You Know? The Fibonacci sequence appears in nature! Sunflowers have 34 or 55 spirals, pinecones have 8 or 13 spirals, and many flowers have 3, 5, 8, or 13 petals. Indian mathematician Virahanka described this sequence around 700 CE — centuries before Fibonacci!

Image needed: The Fibonacci spiral in nature — showing the number sequence, the spiral drawn on squares, and real examples: sunflower head with spiral lines, a shell (nautilus), and a pinecone. Include a small portrait of Virahanka/Indian connection note.
Style: Educational diagram combining the spiral with nature photos/illustrations
Size: 700Ɨ450px

How to Find the Rule of a Pattern

Follow these steps:

StepWhat to DoExample: 3, 7, 11, 15, 19, ...
1Find the differences between consecutive terms7āˆ’3=4, 11āˆ’7=4, 15āˆ’11=4, 19āˆ’15=4
2If differences are constant → Arithmetic (add/subtract)Yes! Constant difference = 4
3If differences are NOT constant, find ratiosNot needed here
4If ratios are constant → Geometric (multiply/divide)—
5If neither, look for other rules (Fibonacci, squares, two-step)—

Two-Step Rules

Some patterns use two operations together:

Example 5: 2, 5, 11, 23, 47, ...

Solution: Differences: 3, 6, 12, 24 — the differences are doubling!

Or think: each term = previous Ɨ 2 + 1

Check: 2Ɨ2+1=5 āœ“, 5Ɨ2+1=11 āœ“, 11Ɨ2+1=23 āœ“, 23Ɨ2+1=47 āœ“

Next term: 47 Ɨ 2 + 1 = 95

Example 6: 1, 4, 9, 16, 25, 36, ...

Solution: These are 1², 2², 3², 4², 5², 6² — square numbers!

Next term: 7² = 49

Example 7: 2, 6, 12, 20, 30, 42, ...

Solution: Differences: 4, 6, 8, 10, 12 — differences increase by 2 each time

Next difference = 14. Next term = 42 + 14 = 56

(These are n Ɨ (n+1): 1Ɨ2=2, 2Ɨ3=6, 3Ɨ4=12, 4Ɨ5=20, 5Ɨ6=30, 6Ɨ7=42, 7Ɨ8=56)

Patterns in Multiplication Tables

Multiplication tables are full of hidden patterns!

The 9-Times Table Pattern

9 Ɨ nAnswerTens DigitOnes DigitDigit Sum
9 Ɨ 109090+9 = 9
9 Ɨ 218181+8 = 9
9 Ɨ 327272+7 = 9
9 Ɨ 436363+6 = 9
9 Ɨ 545454+5 = 9
9 Ɨ 654545+4 = 9

Patterns: Tens digit goes up (0,1,2,3,...), ones digit goes down (9,8,7,6,...), and digit sum is always 9!

Magic Squares

A magic square is a grid where every row, column, and diagonal adds up to the same number (the magic constant).

3Ɨ3 Magic Square (numbers 1-9, magic constant = 15):

276
951
438

Every row, column, and diagonal = 15

Image needed: A colourful 3Ɨ3 magic square with arrows showing how rows, columns, and diagonals all sum to 15. Also show a 4Ɨ4 magic square (like Khajuraho temple magic square from Indian heritage) with magic constant 34.
Style: Colourful grid with arrows and sums marked, Indian temple context
Size: 600Ɨ400px

Did You Know? India has one of the oldest known magic squares! A 4Ɨ4 magic square is carved in the Parshvanath temple in Khajuraho (12th century). Its magic constant is 34. Ancient Indian mathematicians were fascinated by number patterns!

Patterns in Nature and Real Life

WherePatternType
Sunflower seedsFibonacci spirals (34, 55)Fibonacci
HoneycombHexagonal pattern repeatsRepeating geometric
SeasonsSummer, Monsoon, Winter, Spring — repeatsRepeating
Cricket overs6 balls per over, score increasesArithmetic
Bank interest (compound)Amount doubles periodicallyGeometric
Rangoli designsSymmetrical repeating patternsRepeating / symmetry
Train timingsArrive every 15 minutesArithmetic (+15)

Key Words

WordMeaning
PatternA set of numbers/shapes that follow a definite rule
SequenceAn ordered list of numbers following a rule
TermEach number in a sequence
Common DifferenceThe constant amount added/subtracted in arithmetic patterns
Common RatioThe constant multiplier in geometric patterns
Arithmetic PatternAdd or subtract the same number each time
Geometric PatternMultiply or divide by the same number each time
Fibonacci SequenceEach term = sum of two previous terms
Square Numbern Ɨ n (1, 4, 9, 16, 25, ...)
Triangular Number1, 3, 6, 10, 15, ... (sum of first n natural numbers)
Magic SquareGrid where all rows, columns, diagonals have the same sum

Key Points to Remember

  • Arithmetic patterns: add/subtract a constant (common difference)
  • Geometric patterns: multiply/divide by a constant (common ratio)
  • Fibonacci: each term = sum of two previous terms (Indian origin — Virahanka, 700 CE)
  • Square numbers: 1, 4, 9, 16, 25, ... (differences are odd: 3, 5, 7, 9, ...)
  • Triangular numbers: 1, 3, 6, 10, 15, ... (add 2, 3, 4, 5, ...)
  • To find the rule: look at differences first, then ratios, then other rules
  • Some patterns combine two operations (Ɨ2 then +1)
  • The 9-times table: digits always sum to 9
  • Patterns appear everywhere — nature, art, music, sports, daily life

Finished learning? Now test what you know!