Factors: Numbers that divide evenly into another number. For example, the factors of 20 are numbers that divide 20 without leaving a remainder.
- Start with 1 and the number itself
- Check each number up to the square root of the number
- If a number divides evenly, add both the divisor and the quotient
- List all unique factors
1×20=20, 2×10=20, 4×5=20
So factors are: 1, 2, 4, 5, 10, 20
Each factor represents a possible number of groups or marbles per group
1 group of 20 marbles, 2 groups of 10 marbles, 4 groups of 5 marbles, etc.
6 different ways: 1×20, 2×10, 4×5, 5×4, 10×2, 20×1
The grouping with the largest number as groups gives the most groups
20 groups of 1 marble each gives the most groups (20 groups)
Tom can group his 20 marbles in 6 different ways:
1 group of 20, 2 groups of 10, 4 groups of 5, 5 groups of 4, 10 groups of 2, or 20 groups of 1
The grouping with the most groups is 20 groups of 1 marble each.
• Factor identification: Find all numbers that divide 20 evenly
• Application: Each factor pair represents a possible grouping
• Optimization: The largest factor as number of groups gives the most groups
Least Common Multiple (LCM): The smallest positive number that is a multiple of two or more numbers.
Multiples of 10: 10, 20, 30, 40, 50, 60, 70, 80, 90...
Multiples of 15: 15, 30, 45, 60, 75, 90, 105...
The smallest number that appears in both lists is 30
So LCM(10, 15) = 30
They will both arrive together again in 30 minutes
9:00 AM + 30 minutes = 9:30 AM
School bus: 30 ÷ 10 = 3 times (but we started at 0, so 3 additional arrivals)
City bus: 30 ÷ 15 = 2 times (but we started at 0, so 2 additional arrivals)
Total: School bus arrives 4 times (including 9:00), City bus arrives 3 times (including 9:00)
The buses will next arrive together at 9:30 AM.
By that time, the school bus will have arrived 4 times (at 9:00, 9:10, 9:20, 9:30) and the city bus will have arrived 3 times (at 9:00, 9:15, 9:30).
• LCM concept: Find the smallest common multiple of given numbers
• Time calculation: Add LCM minutes to the starting time
• Counting principle: Divide total time by interval to count occurrences
Arithmetic sequence: A sequence where each term increases by a constant amount called the common difference.
5 = 1×5, 10 = 2×5, 15 = 3×5, 20 = 4×5, 25 = 5×5
The nth term is 5n
Using the rule: 5(15) = 75
First 6 terms: 5, 10, 15, 20, 25, 30
Sum = 5 + 10 + 15 + 20 + 25 + 30 = 105
The 15th number in the sequence is 75.
The first 6 figures require 105 stars total.
• Pattern recognition: Identify the rule that generates the sequence
• Formula application: Use the rule to find any term in the sequence
• Series summation: Add consecutive terms to find totals
Rule: 5n
Factors: Numbers that divide evenly into another number
Multiples: Products of a number and any integer
Patterns: Sequences that follow a predictable rule
- Read carefully: Understand what the problem is asking
- Identify key words: Look for terms like "arrange," "together," "sequence," "pattern"
- Choose method: Determine if it's a factor, multiple, or pattern problem
- Solve systematically: Apply the appropriate mathematical operation
- Check answer: Verify your solution makes sense
Greatest Common Factor (GCF): The largest number that divides two or more numbers without leaving a remainder.
Factors of 30: 1, 2, 3, 5, 6, 10, 15, 30
Factors of 45: 1, 3, 5, 9, 15, 45
Common factors: 1, 3, 5, 15
Greatest common factor: 15
Books per packet: 30 ÷ 15 = 2
Notebooks per packet: 45 ÷ 15 = 3
15 packets × 2 books = 30 books ✓
15 packets × 3 notebooks = 45 notebooks ✓
The teacher can make 15 identical reading packets.
Each packet will contain 2 books and 3 notebooks.
• GCF application: Use GCF to find maximum number of identical groups
• Division: Divide total items by group count to get items per group
• Verification: Multiply back to ensure original quantities are preserved
Linear pattern: A pattern where the number of elements increases by a constant amount each time.
Figure 1: 7 tiles, Figure 2: 13 tiles, Figure 3: 19 tiles
Each figure adds 6 tiles: 7, 7+6, 7+6+6, ...
Pattern rule: 6n + 1 (where n is the figure number)
Using the rule: 6(25) + 1 = 150 + 1 = 151 tiles
We already found that the 25th figure has 151 tiles
Let's verify: 6n + 1 = 151 → 6n = 150 → n = 25
Using the rule for n=1 to n=10:
Sum = Σ(6n+1) from n=1 to 10 = 6×Σn + 10 = 6×55 + 10 = 330 + 10 = 340
Or: 7+13+19+25+31+37+43+49+55+61 = 340
25th figure: 6(25) + 1 = 151 ✓
Figure with 151 tiles: n = 25 ✓
First 10 figures: 340 tiles ✓
The 25th figure will contain 151 tiles.
The 25th figure will contain exactly 151 tiles.
The first 10 figures contain 340 tiles combined.
• Pattern recognition: Identify the constant difference between terms
• Formula creation: Develop a rule based on the pattern
• Series summation: Use arithmetic series formulas to find totals
Rule: 6n + 1
Factor: A number that divides another number evenly
Multiple: The product of a number and an integer
Prime Number: A number with exactly two factors (1 and itself)
Composite Number: A number with more than two factors
- Understand: Read the problem carefully and identify what is being asked
- Plan: Decide which mathematical concept to apply (factors, multiples, or patterns)
- Solve: Apply the appropriate method systematically
- Check: Verify your answer makes sense in the context of the problem
• Factor pairs: If a×b = n, then a and b are factors of n
• Multiples: Multiples of n are n, 2n, 3n, 4n, ...
• GCF: Greatest common factor is the largest shared factor
• LCM: Least common multiple is the smallest shared multiple
• Pattern rule: Find the relationship between position and value
Sequence A: 3, 8, 13, 18, 23, ... (start at 3, add 5 each time)
Sequence B: 4, 12, 20, 28, 36, ... (start at 4, add 8 each time)
Sequence C: 1, 9, 25, 49, 81, ... (odd perfect squares)
Analysis: Different sequences follow different rules and grow at different rates.
- Sequence A: Arithmetic sequence (rule: 5n-2)
- Sequence B: Arithmetic sequence (rule: 8n-4)
- Sequence C: Odd perfect squares (rule: (2n-1)²)