🔵Factors & Multiples
A factor of a number divides it exactly (no remainder). Example: the factors of 12 are 1, 2, 3, 4, 6, 12.
A multiple is what you get when you multiply a number by 1, 2, 3, … Example: multiples of 5 are 5, 10, 15, 20, 25, …
Tip: 1 is a factor of every number, and every number is a factor of itself.
👀 See a worked example
List the factors of 8.
Numbers that divide 8 exactly: 1, 2, 4, 8.
Write the first four multiples of 6.
6 × 1, 6 × 2, 6 × 3, 6 × 4 = 6, 12, 18, 24.
🤖 Vidi's Key Points
- A factor divides a number exactly; a multiple is the times-table of a number.
- 1 is a factor of every number; every number is a factor of itself.
- Factors are limited; multiples go on forever.
🟢Prime & Composite Numbers
A prime number has exactly two factors: 1 and itself (e.g. 2, 3, 5, 7, 11).
A composite number has more than two factors (e.g. 4, 6, 8, 9, 12).
Special case: 1 is neither prime nor composite (it has only one factor). 2 is the only even prime.
👀 See a worked example
Is 7 prime or composite?
7's only factors are 1 and 7 → prime.
Is 9 prime or composite?
9 = 1, 3, 9 (three factors) → composite.
🤖 Vidi's Key Points
- Prime = exactly two factors (1 and itself).
- Composite = more than two factors.
- 1 is neither prime nor composite; 2 is the only even prime.
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