Properties of Numbers

Differentiating between odd and even numbers is very simple.

All of the even numbers will end in 2, 4, 6, 8 or 0. Even numbers can all be divided by two.

All of the odd numbers will end in 1, 3, 5, 7 or 9.

People sometimes get confused between factors and multiples.

Factors of a specific number are the numbers that can fit into it exactly when multiplied.

For example, the factors of 20 would be 1, 2, 4, 5, 10 and 20. All of these numbers can be multiplied and fit exactly into 20.

When finding factors, you might find it easier to find them in pair. For 20, you could do this by realising that 2 x 10 = 20 so 2 and 10 are both factors.

Multiples are the numbers of a times table.

For example, the multiple of 6 would be 6, 12, 18, 24, 30 etc.

A prime number is a number that only has itself and 1 as its factors. 7 is a prime number because no number can multiply to make 7 other than 1 x 7.

A square number is a the answer when you multiply a number by itself. For example, 6 x 6 = 36 so, 36 is a square number.

A square root of a number is the number that needs to be multiplied by itself to get the number we have. So if we wanted find the square root of 36, it would be 6 because 6 multiplied by itself would become 36.

There are a few tricks in figuring out which numbers are in certain times tables.

Numbers divisible by 5 will end in 5 or 0

Numbers divisible by 3 will have digits that add up to a number divisible by 3 (eg 84 – 8 + 4 = 12 and 12is divisible by 3)

Numbers divisible by 9 will have digits that add up to a number divisible by 9 (eg 117 – 1 + 1 + 7 = 9 and 9 is divisible by 9)

Numbers divisible by 4 will have the last two digits divisible by 4 (eg 8724 – the last two digits are 24 and 24 is divisible by 4)