We all work with nunbers every day, often without really thinking about them: numbers on the newspaper (prices, dates,amounts); numbers on the television or radio; sporting results; time; labels on food; money; addresses, bar codes and many more.
Natural numbers
Natural numbers are positive integers. E.g. 1, 2, 3, …
Whole numbers
Some authors take whole numbers to be 0, 1, 2, 3, …
Other authors may consider whole numbers as
... –4, –3, –2, –1, 0, 1, 2, 3, 4, ...
which makes whole numbers the same as integers .
Rational numbers
Rational numbers are numbers that can be written as a fraction where the numerator and denominator are integers.
Irrational numbers
Irrational numbers are numbers that are not rational. In other words, they are numbers that cannot be written as fractions.
In decimal form, these numbers go on forever and the same pattern of digits are not repeated.
For example:. pi(
Real numbers
Real numbers are all the rational and irrational numbers.
The following diagram shows the relationship between the types of numbers:
The following video will describe the above types of numbers:
Squares
The square of a number is the number multiplied by itself.
For e.g. square of 4 = 4 2 = (4 × 4) = 16
Perfect squares are squares of whole numbers. Some examples of perfect squares are 12 = 1, 22 = 4, 32 = 9, 42 = 16, 52 = 25, 62 = 36
Square roots
The square root of a number n is the number that gives n when multiplied by itself.
For e.g. square root of 49 = 7 because (7 × 7) = 49
The square root of a perfect square would be a whole number.
Cubes
The cube of a number is the number multiplied by itself twice
For e.g. cube of 4 = 4 3 = (4 × 4 × 4) = 64
Perfect cubes are cubes of whole numbers. Some examples of cubes are 13 = 1, 23 = 8, 33 = 27, 43 = 64, 53 = 125, 63 = 216
Cube roots
The cube root of a number n is the number that gives n when multiplied by itself twice.
For e.g. cube root of 27 = 3 because (3 × 3 × 3) = 27
The cube root of a perfect cube would be a whole number.
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) = 3.142.. and 
= 1.4142….
