## Sets of numbers

Numbers can be categorized in different sets of numbers.
The category the number belongs to, tells us what kind of number it is.

## The most common sets of numbers

 Symbol Name Description Examples Natural numbers All positive whole numbers. 1, 2, 3, 4, .... Natural numberswith zerro All positive whole numbers including zero. 0, 1, 2, 3, 4, .... Integers All whole numbers, positive and negative, including zero.That is, number that can be written without use of fractionsor decimals. ..... -3, -2, -1, 0, 1,2, 3, .... Rational numbers All integers including zero or all numbers expressed asfractions of two integers, the denominator of which is not zero. 510 Irrational numbers All numbers that cannot be expressed as a simple fractionor decimal number. All square rootsof primes. Real numbers All sets of numbers above are contained in the set ofreal numbers. So it is all positive and negative wholenumbers, zero, fractions, decimal numbers, square rootsor pi. 510.233.1415926535... (Pi)