In KS2 Maths, children learn about special things about numbers. In Year Six, they get really good at multiples and factors. They also get to know square numbers and what prime numbers are.

Numbers have special things called square numbers, factors, multiples, and prime numbers. Understanding these things helps us see how numbers are friends. Like, what's a square number or a prime number? A square number is when you times a number by itself. And a prime number is special because its only friends are itself and 1.

Do you know about these number friends? Take a fun quiz for 10-11 year olds and find out more about the magic of numbers!

Discover the Joy of Learning Together with Quizzes1.

Which are the factors of 24?

1, 2, 3, 4, 6, 8, 12, 24

2, 3, 4, 6, 8, 12

1, 2, 3, 4, 5, 8, 12, 24

1, 2, 4, 6, 12, 24

Remember that every number is a factor of itself as it is itself multiplied by 1

2.

What is a prime number?

A number that is only divisible by 1 and itself

A number that cannot be squared

A whole number that divides into another whole number

An odd number that is divisible by 3

For a number to be prime it must have 2 different factors, therefore 1 is not counted as a prime number

3.

How can we recognise if a number is divisible by 6?

A number is divisible by 6 if it is odd and divisible by 3

A number is divisible by 6 if it is even and divisible by 3

A number is divisible by 6 if the sum of its digits total 3

A number is divisible by 6 if it is even and divisible by 2

96 is divisible by 6 because it is also divisible by 3 and it is even

4.

How can we recognise if a number is divisible by 9?

A number is divisible by 9 if it is an odd number

A number is divisible by 9 if the sum of its digits is divisible by 9

A number is divisible by 9 if the last two digits are divisible by 4

A number is divisible by 9 if the sum of its digits total 3

468 is divisible by 9 because 4 + 6 + 8 = 18 and 18 = 2 x 9

5.

What is the next prime number after 7?

9

11

13

27

Here are all the prime numbers between 1 and 50

2 - 3 - 5 - 7 - 11 - 13 - 17 - 19 - 23 - 29 - 31 - 37 - 41 - 43 - 47

2 - 3 - 5 - 7 - 11 - 13 - 17 - 19 - 23 - 29 - 31 - 37 - 41 - 43 - 47

6.

How can we recognise if a number is divisible by 25?

A number is divisible by 25 if it ends in 00, 25, 50 or 75

A number is divisible by 25 if it is divisible by 8

A number is divisible by 25 if the last two digits are divisible by 8

A number is divisible by 25 if it is odd and divisible by 3

Despite it being a relatively large number, the 25 times table is quite easy to learn

7.

What is 15 squared?

150

175

225

250

One way to work this out is to multiply 15 by 10 (150), then half it (75) and add the two answers together (150 + 75 = 225)

8.

How can we recognise if a number is divisible by 8?

A number is divisible by 8 if it is a square number

A number is divisible by 8 if it ends in 2 or 4

A number is divisible by 8 if the last two digits are divisible by 8

A number is divisible by 8 if the last three digits are divisible by 8

Or if half the number is divisible by 4

9.

Which is the smallest common factor of 6 and 15?

2

3

5

6

3 is in fact the only common factor of 6 and 15

10.

How can we recognise if a number is divisible by 3?

A number is divisible by 3 if it is an odd number

A number is divisible by 3 if it ends in 3

A number is divisible by 3 if the sum of its digits is divisible by 3

A number is divisible by 3 if it is a square number

642 is divisible by 3 because 6 + 4 + 2 = 12; 12 is divisible by 3