Numbers

Most important object in mathematics is NUMBERS, as we have to use them everywhere in mathematics. We use numbers for counting, measuring and labeling purposes. Though we use lot of numbers in our day to day life, most students don't know the basics of numbers. If we consider about the history of numbers, it has a very long story which runs through several civilizations. If you need further details about the history of numbers you can visit this wiki article.

The set of numbers can be categorized in to different subsets. But we must keep in our mind that there is a hierarchy for these subsets as some of them are subsets of others. Namely this number system can be divided into Real Numbers, Complex Numbers, Rational Numbers and Integers etc. Following figure shows the hierarchy of the Number System.

Number System

Rational numbers can be categorize as follows, but one category can be a subset of another. ex- Natural numbers is a subset of Integers.

Rational Numbers

If we consider about Decimal numbers, Irrational numbers are also decimal numbers. But they cannot be categorize under Finite or Recurring Decimals. Following table can be use for understanding more about numbers.