Prime or composite, step by step
A prime number has exactly two factors: one and itself.
The question
Is 24 prime or composite?
Is 24 prime?
24
√24≈4
tried:2
24 ÷ 2 =12
- A prime has exactly two factors: 1 and itself. So the question is whether anything ELSE divides into 24.
- You do not have to try everything up to 24. Factors come in pairs, so if one were bigger than 4 its partner would be smaller — and you would have found that one first. Testing up to 4 is enough.
- 2 goes into 24 exactly (24 ÷ 2 = 12), and that is one factor too many. 24 is composite — no need to test any further.
How it works.
- 01
A prime has exactly two factors: 1 and itself. So the question is whether anything ELSE divides into 24.
- 02
You do not have to try everything up to 24. Factors come in pairs, so if one were bigger than 4 its partner would be smaller — and you would have found that one first. Testing up to 4 is enough.
- 03
2 goes into 24 exactly (24 ÷ 2 = 12), and that is one factor too many. 24 is composite — no need to test any further.