 # Numbers

A number is a symbol used to represent either a position (like when asking who finished last), a quantity (like when asking how many bananas you want to buy), or a magnitude (like when asking how fast a car is going). There were a few ways to represent them in the past, but these days we basically use two kinds of numerals (number symbols), Roman and Arabic figures.

Roman numerals include the letters I, V, X, L, C, D and M. We usually use them to indicate set figures like years or chapter numbers.

Arabic numerals include combinations of the symbols 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. We use them every day, and we use auxiliary symbols to complete the figures we want to express. These are the ones we use most for mathematical operations.

Numbers are the grounds of all sciences. This is why they are very important. Since very old times mankind has trusted mathematics to advance as species. This, because mathematics and its derivative sciences have allowed man to, for example:

+ Leave barter as the main way to exchange things and allow the raise of economy through currency.
+ Build bridges which would not fall.
+ Fight diseases through medicine.

Without mathematics, human life would still be very primitive.

## Types of numbers

There are two kinds of numbers nowadays: the ones we use to indicate position (called ordinal), and the ones we use to indicate either quantity or magnitude (called cardinal).

## Kinds of numbers

In addition to this, you should know that the progress of societies eventually led to the definition of a few kinds of numbers. For ease, they are now divided into the following groups. Note that the largest group includes all the others. From smaller to larger, these groups are:

Natural numbers, which appeared as a consequence of counting things, for example, one hammer.

Integer numbers, which very likely appeared when man understood the concept of debt.
Example: If you owe me four eggs, then you have minus four eggs because the first four you get are for you to pay me back, the rest are yours.

Fractions and decimal numbers, which appeared when man understood the concept of part. They are also known as rational numbers.
Example: If you don't want this huge watermelon, I can still sell you a part of it for a coin.

Irrational numbers, which appeared when man noticed not all numbers could be represented using a fraction, like when they found the value of pi.

Complex numbers, which appeared when man found calculations in which they could not define the square root of a negative number.

Continue with... number names

Learn + Mathematics