SME
Grade 4 Math · Operations & Algebraic Thinking
Factors, multiples and patterns
Use this for “Find all the factor pairs of 24. Is 24 prime or composite?”
Diagram
24 has 4 factor pairs: 1 × 24, 2 × 12, 3 × 8, 4 × 6.
It is composite.
This is an example. Type your own values to start a new problem.
One factor
×
Its partner
=
Number
Number of factors
worked out (not typed)
Formulas
4 × 6 = 24
One factor × its partner = number
24 has 8 factors
Count every factor of the number = number of factors
Assumptions
•
A factor pair is two whole numbers that multiply to make the number.
•
Find every pair by trying 1, 2, 3, … until the factors would swap places.
•
A prime number has exactly 2 factors: 1 and itself. A composite number has more.
•
The picture shows every factor pair as a rectangle. A prime number has only one.
•
Numbers to 200 (the factors of 105 or 126).
Step-by-step
WE KNOW
One factor: 4
Its partner: 6
FIND
number, number of factors
Step 1 · Find number
4 × 6 = ?
One factor × its partner = number
Multiply the factor pair to get the number.
Number = 24
Step 2 · Find number of factors
24 has ? factors
Count every factor of the number = number of factors
List every factor pair from 1 up. Count the factors once each.
Factor pairs of 24: 1 × 24, 2 × 12, 3 × 8, 4 × 6
Factors: 1, 2, 3, 4, 6, 8, 12, 24 → 8
Number of factors = 8 (24 is composite: more than 2 factors)
Check
Put the numbers back in. Both sides should match.
4 × 6 = 24 ✓
24 has 8 factors ✓
Topic check
See what you know: 5 questions on this topic
New questions each time. Pass to mark it complete.
Refresh
Nothing to review first. This is a starting point.
More problem types
Identify multiples
Use this for “Is 27 a multiple of 4?” or “Is 40 a multiple of 8?”
Number patterns
Use this for “Start at 3 and add 5 each time: 3, 8, 13, … What is the 5th number?”
Number patterns: find the rule
Use this for “What comes next? Write the rule” when a pattern adds, multiplies or takes turns between two steps.
Prime and composite numbers
Use this to sort numbers as prime or composite by their factors.
Shape patterns
Use this for “Circle, square, triangle, circle, square, … What is the 10th shape?”