Is -249 an Odd Number?

-249: even or odd number?

A number is odd if it is not divisible by 2.


The number -249 is odd, because it is not divisible by 2: the remainder is 1 when divided by 2.


How to recognize an odd number: its last digit, the one that is in the ones place (the first digit of the number counted from the right), is: 1, 3, 5, 7 or 9.


Mathematically, the odd numbers can be written as:
2 × k + 1, where k ∈ Z, the set of integer numbers


The number -249 is odd.

Operating rules (scroll down...)

When working with even and odd numbers, the following rules apply:

Addition:
even + even = even; even + odd = odd; odd + odd = even
Examples:
2 + 4 = 6 (even); 1 + 2 = 3 (odd); 1 + 3 = 4 (even).


Subtraction:
even - even = even; even - odd = odd; odd - odd = even
Examples:
4 - 2 = 2 (even); 2 - 1 = 1 (odd); 3 - 1 = 2 (even).


Multiplying:
even × even = even; even × odd = even; odd × odd = odd
Examples:
2 × 4 = 8 (even); 2 × 3 = 6 (even); 3 × 5 = 15 (odd).




1. Tutoring: Even or odd? Integer numbers parity. 2. Examples of even and odd numbers. 3. The last digit of numbers. 4. Formal definition

1. Numbers' parity: even or odd?

  • An integer is called an even number if it is divisible by 2; in other words, an integer is called an even number if there is no remainder when dividing it by 2.
  • An integer is called an odd number if it is not divisible by 2, in other words, if there is a remainder of 1 when dividing it by 2.
  • If a number is even then it is not an odd number.
  • The property of an integer of being either even or odd is called parity.

2. Examples of even and odd numbers:

  • Even numbers: -14, 2, 0, 8, 56, and 127,388 (there is no remainder when divided by 2).
  • Odd numbers: -13, 1, 5, 97, 19, and 127,387 (all leave a remainder of 1 when divided by 2).
  • All the prime numbers except the number 2 are odd numbers.

3. The numbers' last digit

  • An integer number is even or odd depending on whether its last digit is even or odd.
  • If the last digit of a number is 0, 2, 4, 6, or 8, then the number is even.
  • If the last digit of a number is 1, 3, 5, 7, or 9, then the number is odd.

4. Formal definition of even and odd numbers:

  • An even number, "a", can always be written as the product between 2 and some other integer, "k".
  • The even number a = 2 × k
  • As a result, an odd number, "b", since it leaves a remainder of 1 when divided by 2, can always be written as the product between 2 and some other integer, "k", plus 1.
  • The odd number b = 2 × k + 1

Did you know?

  • In some countries the houses are numbered so that the ones on one side of the street have even numbers and the ones on the other side have odd numbers.