Factors of 4
The factors of 4 are 1, 2, 4. 4 is a composite number with 3 factors. Prime factorisation: 2^2.
All 3 factors of 4
1, 2, 4
A factor divides 4 exactly, with no remainder. Every factor has a partner: the pairs below multiply to 4. The negative factors are -1, -2, -4, because a negative times a negative is positive.
Factor pairs of 4
| Pair | Product |
|---|---|
| 1 × 4 | 4 |
| 2 × 2 | 4 |
Stop at the square root (2): every pair after that is one you already have, the other way round.
Prime factorisation of 4: 2^2
| Divide | by the smallest prime | Result |
|---|---|---|
| 4 | 2 | 2 |
| 2 | 2 | 1 |
So 4 = 22, that is 2 × 2.
The number of factors comes from the exponents: (2 + 1) = 3.
How to find the factors of 4
- Start with 1 and 4: every number has those two.
- Test 2, 3, 4, … up to the square root of 4, which is about 2.
- Each time a number divides exactly, write it down with its partner (the quotient).
- Use the divisibility rules to skip work: by 2 yes (the last digit is even); by 3 no (the digit sum is 4); by 5 no (the last digit is 4).
- Put the list in order: 1, 2, 4.
🧮 Calculator
The answer appears here, with the working in words.
✏️ Five questions, answers hidden
1. List the factors of 5.
Answer: 1, 5
2. Write the prime factorisation of 8.
Answer: 2^3
3. How many factors does 4 have?
Answer: 3
4. What is the largest factor of 4 other than itself?
Answer: 2
5. Is 6 prime or composite?
Answer: composite
📚 The class this belongs to
Factors are taught in Grade 4 and 5 in the US, Year 5 and 6 in the UK, Class 4 to 6 in CBSE (NCERT Class 6, Playing with Numbers) and Year 5 and 6 in Australia.
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