# Counting

Counting is the mathematical action of adding (or subtracting) one, usually to find out how many objects there are or to set aside a desired number of objects (starting with one for the first object and proceeding with a one-to-one correspondence). However, counting is also used (primarily by children) to demonstrate knowledge of the number names and the number system.

Counting sometimes involves numbers other than one -- for example, when counting money, or counting out change, or when "counting by twos" (2, 4, 6, 8, 10, 12, ...) or when "counting by fives" ( 5, 10, 15, 20, 25 ...).

There is archeological evidence that humans have been counting for at least 50,000 years [1 - p.9]; the development of counting led to the development of mathematical notation and numeral systems. Counting was primarily used by ancient cultures to keep track of economic data such as debts and capital.

## References

1. An Introduction to the History of Mathematics (6th Edition) by Howard Eves (1990)de:Zählen