# Integer

An integer is a number that has no fractional part, and no digits after the decimal point. An integer can be positive, negative or zero. (Compare this to real numbers than can have digits after the point and can have fractional parts)

Example integers: 12 , 34 , -4 , 0

The following are real numbers and are not integers:

• 1.23 (cannot have decimal places)
• 12½ (cannot have a fractional part).

Try this Drag the orange dot below to move it along the number line. Note how it only stops at the integers.

## Whole numbers and counting numbers

Whole numbers (sometimes called 'counting numbers') are like integers, but they cannot be negative. They are usually used to indicate the number of objects. Example: 12 students.

## Rounding

Real numbers can be converted to integers by rounding. This means removing the decimal digits and adjusting the result to be the nearest integer to the original number. See Rounding for more.

## Pages referring to 'integer'

An overview of the types of numbers that are used in math. Links to other pages explaining each type in depth. Explains also that some numbers are not numbers at all.
While you are here..

... I have a small favor to ask. Over the years we have used advertising to support the site so it can remain free for everyone. However, advertising revenue is falling and I have always hated the ads. So, would you go to Patreon and become a patron of the site? When we reach the goal I will remove all advertising from the site.

It only takes a minute and any amount would be greatly appreciated. Thank you for considering it!   – John Page

Become a patron of the site at   patreon.com/mathopenref