The numbers 1, 2, 3, 4, 5.... are called the natural numbers, or sometimes, the counting numbers.
They are members of an infinite set of numbers of the form 123*k where k is an integer.
7
This set of numbers is called "Whole Numbers".
The set of real numbers.
two numbers which are equal to 123:123 + 0122 + 1121 + 2120 + 3 ...
real numbers
The set of natural numbers. The set already has the zero in it.
With 123 digits you can make 123 one-digit numbers.
a set
The set of numbers that include the natural numbers, their opposites and 0 is called the set of integers.
123 123 123
A set with no numbers in it; also called an empty set.