Odd and even numbers

Last updated: 18 Aug 2008

Even numbers are all the numbers which have no remainder when divided by 2, for example -312, 0 and 4.

Odd numbers are all numbers which have a remainder of 1 when divided by 2, for example -7, 1 and 245.

Combining odd and even numbers

If x and y are both even then x + y and xy are both even. For example 2 + 8 = 10 and 2 x 8 = 16.

If x and y are both odd then x + y is even and xy is odd. For example 3 + 5 = 8 and 3 x 5 = 15.

If x is even and y is odd then x + y is odd and xy is even. For example 6 + 7 = 13 and 6 x 7 = 42.

Next page: Prime numbers

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