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.
Other number topics
Scalar numbers
Counting numbers
Numbers that have factors
Special values
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