Number Patterns - Fifth Grade
Complete Notes & Formulas
What is a Number Pattern?
A number pattern (or sequence) is an ordered list of numbers that follow a specific rule. The rule tells us how to get from one number to the next.
Parts of a Pattern
Terms: The numbers in a pattern
Rule: The instruction for finding the next term
First term: The starting number
Types of Number Patterns
Type | Description | Example |
---|---|---|
Increasing | Numbers get larger | 2, 5, 8, 11, 14... |
Decreasing | Numbers get smaller | 50, 45, 40, 35, 30... |
Repeating | A set of numbers repeats | 1, 2, 3, 1, 2, 3... |
Multiplication | Multiply by same number | 3, 6, 12, 24, 48... |
1. Use a Rule to Complete a Number Pattern
What is a Pattern Rule?
A pattern rule is an instruction that tells you how to find the next number in a sequence.
Common Pattern Rules
Addition Rule: Add the same number each time
Example: Add 5 → 3, 8, 13, 18, 23...
Subtraction Rule: Subtract the same number each time
Example: Subtract 7 → 100, 93, 86, 79, 72...
Multiplication Rule: Multiply by the same number each time
Example: Multiply by 2 → 5, 10, 20, 40, 80...
Division Rule: Divide by the same number each time
Example: Divide by 3 → 81, 27, 9, 3, 1...
Combined Rules: More than one operation
Example: Add 3, then subtract 1 → 10, 13, 12, 15, 14...
Steps to Complete a Pattern
Step 1: Look at the given numbers
Step 2: Find the difference or relationship between consecutive terms
Step 3: Identify the rule (add, subtract, multiply, divide)
Step 4: Apply the rule to find missing numbers
Step 5: Check your answer by applying the rule again
Examples
Example 1: Complete the pattern: 7, 12, 17, 22, __, __
Step 1: Find the difference
12 - 7 = 5, 17 - 12 = 5, 22 - 17 = 5
Step 2: Rule: Add 5
Step 3: Apply the rule
22 + 5 = 27, 27 + 5 = 32
Answer: 27, 32
Example 2: Complete: 80, 72, 64, __, __, 40
Difference: 72 - 80 = -8 (subtract 8)
Rule: Subtract 8
64 - 8 = 56, 56 - 8 = 48
Answer: 56, 48
Example 3: Rule: Start at 5, add 1, then add 2, then add 3, and so on
5 + 1 = 6
6 + 2 = 8
8 + 3 = 11
11 + 4 = 15
15 + 5 = 20
Pattern: 5, 6, 8, 11, 15, 20...
2. Compare Patterns
What Does It Mean to Compare Patterns?
Comparing patterns means looking at two or more patterns and finding how they are similar or different.
Ways to Compare Patterns
1. Compare Rules: Are the rules the same or different?
2. Compare Terms: Which pattern has larger/smaller numbers?
3. Compare Growth Rate: Which pattern increases/decreases faster?
4. Compare Relationships: Is one pattern related to the other?
Steps to Compare Patterns
Step 1: Write both patterns
Step 2: Find the rule for each pattern
Step 3: Compare corresponding terms (1st to 1st, 2nd to 2nd, etc.)
Step 4: Look for relationships or patterns between the two sequences
Examples
Example 1: Compare these patterns
Pattern A: 3, 6, 9, 12, 15... (Rule: Add 3)
Pattern B: 5, 10, 15, 20, 25... (Rule: Add 5)
Comparison:
• Both are increasing patterns
• Pattern B grows faster than Pattern A
• Pattern B terms are always larger
• Both patterns share the number 15
Example 2: Compare related patterns
Pattern A: 2, 4, 6, 8, 10... (Rule: Add 2)
Pattern B: 4, 8, 12, 16, 20... (Rule: Add 4)
Relationship:
Pattern B = Pattern A × 2
Every term in B is double the corresponding term in A
Example 3: Using a table to compare
Position | Pattern A (×3) | Pattern B (×5) | Difference |
---|---|---|---|
1 | 3 | 5 | 2 |
2 | 6 | 10 | 4 |
3 | 9 | 15 | 6 |
The difference between patterns increases by 2 each time!
3. Complete an Increasing Number Pattern
What is an Increasing Pattern?
An increasing pattern (also called a growing pattern) is a sequence where each term is greater than the previous term.
Types of Increasing Patterns
1. Constant Addition Pattern
Add the same number each time
Example: 10, 15, 20, 25, 30... (Add 5)
2. Increasing Addition Pattern
The amount you add increases each time
Example: 2, 3, 5, 8, 12... (Add 1, add 2, add 3, add 4)
3. Multiplication Pattern
Multiply by the same number each time
Example: 2, 6, 18, 54... (Multiply by 3)
How to Find the Rule
Find the difference between consecutive terms
Examples
Example 1: Complete: 13, 18, 23, 28, __, __, __
Find differences:
18 - 13 = 5
23 - 18 = 5
28 - 23 = 5
Rule: Add 5
28 + 5 = 33, 33 + 5 = 38, 38 + 5 = 43
Answer: 33, 38, 43
Example 2: Complete: 1, 3, 6, 10, 15, __, __
Find differences:
3 - 1 = 2
6 - 3 = 3
10 - 6 = 4
15 - 10 = 5
Rule: Add 2, then 3, then 4, then 5... (increases by 1 each time)
15 + 6 = 21, 21 + 7 = 28
Answer: 21, 28
4. Complete a Multiplication Number Pattern
What is a Multiplication Pattern?
A multiplication pattern is a sequence where each term is found by multiplying the previous term by the same number.
Formula
Next Term = Previous Term × Common Ratio
How to Find the Multiplier
Divide any term by the previous term
Multiplier = Second Term ÷ First Term
Common Multiplication Patterns
Multiplier | Pattern Example |
---|---|
×2 (Double) | 3, 6, 12, 24, 48, 96... |
×3 (Triple) | 2, 6, 18, 54, 162... |
×4 | 1, 4, 16, 64, 256... |
×5 | 2, 10, 50, 250, 1250... |
Examples
Example 1: Complete: 4, 12, 36, __, __
Find multiplier:
12 ÷ 4 = 3
36 ÷ 12 = 3
Rule: Multiply by 3
36 × 3 = 108, 108 × 3 = 324
Answer: 108, 324
Example 2: Complete: 5, 10, 20, 40, __, __
Multiplier: 10 ÷ 5 = 2
Rule: Multiply by 2 (doubling pattern)
40 × 2 = 80, 80 × 2 = 160
Answer: 80, 160
Example 3: Find the 6th term: 3, 15, 75, 375, ...
Multiplier: 15 ÷ 3 = 5
5th term: 375 × 5 = 1,875
6th term: 1,875 × 5 = 9,375
Answer: 9,375
5. Number Patterns: Word Problems
Real-Life Applications
Number patterns appear in many real-world situations like:
• Saving money regularly
• Growing plants or populations
• Building structures with blocks
• Seating arrangements at events
• Distance traveled at constant speed
Steps to Solve Word Problems
Step 1: Read the problem carefully
Step 2: Identify the pattern in the situation
Step 3: Write the first few terms as numbers
Step 4: Find the rule
Step 5: Apply the rule to answer the question
Examples
Problem 1: "Maya saves $5 in week 1, $10 in week 2, $15 in week 3. If this pattern continues, how much will she save in week 6?"
Identify pattern: 5, 10, 15...
Rule: Add $5 each week
Continue:
Week 4: $20
Week 5: $25
Week 6: $30
Answer: Maya will save $30 in week 6
Problem 2: "A bacteria colony doubles every hour. If there are 8 bacteria at 1:00 PM, how many will there be at 4:00 PM?"
Identify pattern: Doubling (×2)
1:00 PM: 8 bacteria
2:00 PM: 8 × 2 = 16
3:00 PM: 16 × 2 = 32
4:00 PM: 32 × 2 = 64
Answer: 64 bacteria at 4:00 PM
Problem 3: "A theater has 20 seats in row 1, 25 seats in row 2, 30 seats in row 3. If this pattern continues, how many seats are in row 8?"
Pattern: 20, 25, 30...
Rule: Add 5 seats per row
Row 4: 35, Row 5: 40, Row 6: 45, Row 7: 50, Row 8: 55
Answer: Row 8 has 55 seats
6. Number Patterns: Mixed Review
Practice All Pattern Types
Mixed review includes all types of patterns: addition, subtraction, multiplication, division, and complex patterns.
Problem-Solving Strategy
1. Look: Examine the given terms
2. Think: Ask yourself questions:
• Are numbers getting larger or smaller?
• Is there a constant difference?
• Is multiplication or division involved?
• Is the pattern more complex?
3. Test: Check if your rule works for all terms
4. Apply: Use the rule to complete the pattern
Mixed Practice Examples
Problem 1: 100, 90, 80, 70, __, __
Type: Decreasing pattern
Rule: Subtract 10
Answer: 60, 50
Problem 2: 2, 6, 18, 54, __, __
Type: Multiplication pattern
Rule: Multiply by 3
Answer: 162, 486
Problem 3: 1, 4, 9, 16, 25, __, __
Type: Square numbers (1², 2², 3², 4², 5²...)
Next terms: 6² = 36, 7² = 49
Answer: 36, 49
Problem 4: 10, 12, 15, 19, 24, __, __
Type: Variable addition (complex pattern)
Differences: +2, +3, +4, +5...
24 + 6 = 30, 30 + 7 = 37
Answer: 30, 37
Problem 5: 5, 10, 8, 16, 14, 28, 26, __, __
Type: Alternating pattern
Rule: Double, then subtract 2
26 × 2 = 52, 52 - 2 = 50
Answer: 52, 50
Quick Reference: Pattern Rules
Operation | How to Find Rule | Example |
---|---|---|
Addition | Subtract consecutive terms | 4, 9, 14, 19 → Add 5 |
Subtraction | Subtract consecutive terms | 50, 42, 34, 26 → Subtract 8 |
Multiplication | Divide consecutive terms | 3, 12, 48, 192 → Multiply by 4 |
Division | Divide consecutive terms | 1000, 100, 10, 1 → Divide by 10 |
💡 Important Tips to Remember
✓ Always check your rule by testing it on all given terms
✓ Look for patterns in the differences between consecutive terms
✓ Increasing patterns: Terms get larger (add or multiply)
✓ Decreasing patterns: Terms get smaller (subtract or divide)
✓ Some patterns may have more than one rule (alternating patterns)
✓ Multiplication patterns grow much faster than addition patterns
✓ Write down your work step-by-step to avoid mistakes
✓ In word problems, identify the numbers before finding the pattern
✓ Practice makes perfect - the more patterns you solve, the easier they become!
🧠 Memory Tricks for Finding Pattern Rules
For Addition/Subtraction Patterns:
Ask: "What do I add or subtract to get from one number to the next?"
For Multiplication/Division Patterns:
Ask: "What do I multiply or divide by to get from one number to the next?"
The "STOP" Method:
See the pattern
Test your rule
Operate to find next terms
Prove it works!
If stuck, try this:
1. Check if it's skip counting (2, 4, 6... or 5, 10, 15...)
2. Check if it's doubling (×2) or tripling (×3)
3. Check if there's an alternating pattern (two rules taking turns)
Master Number Patterns! 🔢🎯
Patterns are everywhere - in math, nature, music, and art!