Focus on Numbers

what is a number?

We can’t quite talk of mathematics without talking about numbers. Numbers in simple terms can be a figure, symbol or word(s) that describe the value (count and size) of things. In this topic we will use Arabic (such as 1,2,3,4....) digits to represent numbers. Click hereto know other ways of counting/types of number.

Natural numbers

A natural number is a number naturally occurring in the nature. Some definitions call it a counting number.As such, a natural number is a whole non negative (may or may not include ZERO)denoted by N 
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N = {0, 1, 2, 3, ...}
‍N = (1, 2, 3, 4, ...} 

N is a denumerable (denumerable means; able to be counted none to one correspondence with infinite set of integers)Natural numbers are the basis in which all other numbers are a made. For instance, adding 0 (if it is not ready included) and additive inverse to make integers. (check definition of integers)

Integers

Integers are whole numbers, both negative and positive, including zero.These numbers are …, -3, -2, -1, 0, 1, 2, 3, …. Positive integers are integers greater than zero, and negative integers,  are integers less than zero. integers will be commonly represented in a number line this course.

consider the figure below.