# Numbers

However scary numbers may be for some of us, one thing is for sure: we cannot escape them. They are mathematical objects, they are represented through symbols we use to express their value. Still, in common language, a number means the symbol and the value. Numbers are used for counting, measuring , identifying and so on and so forth. Modern life would be impossible without numbers. Just think of the serial numbers, the codes such as ISBNs. Not to mention the importance of numerical operations, not only to the economy but to every aspect of life too. Numerical operations can be unary or binary. In unary operations, one number comes in as an input and one number comes out as a result. Binary operations, on the other hand, take two numbers as an input, but one single number comes out as a result. You all know about addition, subtraction, division and multiplication. The science that studies numerical operations like these is called arithmetic. It’s the science of numbers that scares off most kids in school.

There are many sorts and categories that we maybe learn about in school and never think of them again ever after. Maybe you’ve heard of positive and negative numbers, rational and irrational numbers and so on and so forth. Oh, and let us not forget about the number called “zero”, without which banking, computing and other wonderful things would be utterly impossible. The Greeks new about zero and the Babylonians invented its ancestor. But the true origins of zero might be more connected to ancient India and the concept of “nothing” and “nothingness”.

Natural numbers are the ones we use for counting. Originally, counting started with one and zero was not even taken into consideration. Rational numbers are the ones which can be expressed as fractions and real numbers include all the known measurable numbers. While each and every rational number is a real number, not every real number is also a rational number. Complex numbers are those which reach a considerably higher level of abstraction. They are real but they are definitely different from the rational ones.

Algebraic, surreal, hyperreal, these are all different number categories. You’ve surely heard of computable numbers: computable numbers are real numbers which can be computed to within any precision by a finite algorithm.

Now, if you want to learn more about what the algorithm itself is, or if you maybe want to find out more details on different arithmetic categories, visit arithmetic.com. It’s just a click away, it’s easy to use, it explains various interesting arithmetic concepts in an accessible language and it’s all free. Get rid of that strange uncomfortable feeling left to you by long forgotten math classes. Arithmetic is not boring and it’s not too complicated for you. Learn to discover it and understand it. It’s all very simple and rational and it can be fun! Try arithmetic.com!