Factors are numbers that divide exactly into another number. To find all the factors of 20, it's best to work in pairs.
1. Start with 1: 1 × 20 = 20. So, 1 and 20 are factors.
2. Try 2: 2 × 10 = 20. So, 2 and 10 are factors.
3. Try 3: 20 is not divisible by 3.
4. Try 4: 4 × 5 = 20. So, 4 and 5 are factors.
5. The next number to try is 5, which we already have. So we have found all the pairs.
List them in order: 1, 2, 4, 5, 10, 20.
Full Answer
1, 2, 4, 5, 10, 20
A factor of a number is an integer that divides into that number without leaving a remainder. A systematic way to find all factors of 20 is to check each integer starting from 1.
- 20 ÷ 1 = 20 (so 1 and 20 are factors)
- 20 ÷ 2 = 10 (so 2 and 10 are factors)
- 20 ÷ 3 = 6 remainder 2 (so 3 is not a factor)
- 20 ÷ 4 = 5 (so 4 and 5 are factors)
Once the numbers you are checking meet in the middle (e.g., after 4 comes 5, which is already listed), you have found all the factors.
The factors of 20 are 1, 2, 4, 5, 10, 20.
Common mistakes
✗ Forgetting some factors, especially 1 and the number itself (20).\n✗ Listing multiples instead of factors (e.g., 20, 40, 60...).
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