A factor is a whole number which divides exactly into a whole number, leaving no remainder.
For example, 13 is a factor of 52 because 13 divides exactly into 52 (52 ÷ 13 = 4 leaving no remainder).
The complete list of factors of 52 is: 1, 2, 4, 13, 26, and 52 (all these divide exactly into 52).
A prime number has exactly two factors, 1 and itself.
For example, 13 is a prime number because the only factors of 13 are 1 and 13.
The number 8 is not prime because it has four factors: 1, 2, 4 and 8.
The number 1 is not a prime number because it only has one factor (itself).
Work out the factors of each number then click on the button marked to see whether you are correct.
|The factors of 1 are|
|The factors of 2 are|
|The factors of 3 are|
|The factors of 4 are|
|The factors of 5 are|
|The factors of 6 are|
|The factors of 7 are|
|The factors of 8 are|
|The factors of 9 are|
|The factors of 10 are|
Which of the numbers 1 to 10 are prime numbers?
|Is the number 18 prime?|
|Is the number 45 prime?|
|Is the number 79 prime?|
|Is the number 90 prime?|
|Is the number 97 prime?|
(a) What are the factors of 24?
(b) What are the prime factors of 24?
In this section you need to give a list of numbers for some of the answers.
The order doesn't matter, but separate the numbers with commas, like this: