Home learning focus
In this lesson, you will learn about factors, square numbers and prime numbers.
This lesson includes:
- a video
- a learning summary
- three activities
A factor is a number that divides into another number exactly and without leaving a remainder.
The number 12 has six factors:
1, 2, 3, 4, 6 and 12
If 12 is divided by any of the six factors then the answer will be a whole number.
For example: 12 ÷ 3 = 4
Square numbers are formed by multiplying a number by itself. All square numbers have an odd number of factors. For example, the number 25 has three factors:
1, 5 and 25
And the number 16 has five factors:
1, 2, 4, 8 and 16
A prime number is a number which is only divisible by 1 and itself. Prime numbers cannot be divided by another number to leave a whole number.
Prime numbers include:
2, 3, 5, 7, 11, 13, 17, 19, 23 and 29.
The number 59 is prime because it is only divisible by 1 and 59.
The number 51 is not prime because it is divisible by 3 and 17 as well as 1 and 51.
The number 1 only has one factor (itself). Therefore, 1 is not a prime number.
Find out how much you know about factors in this short quiz!
Find the factors
Have a go at this interactive activity from My Maths, Oxford University Press.
Find the factors of different numbers.
Watch out - if you select two incorrect answers it's game over!
There's more to learn
Have a look at these other resources around the BBC and the web.