# Definition:Tally Marks

## Definition

Tally marks are a system of recording (usually) small numbers.

For each unit in a given natural number, a mark is made.

Thus, for example, $13$ could be recorded $|||||||||||||$.

It is usual for tally marks to be arranged in groups of $5$, by drawing every fifth line diagonally across the group of $4$ before it.

Thus $13$ would then be recorded:

## Historical Note

Tally marks are the earliest known records of numbers.

However, the technique is still useful, for example, when recording the number of instances of events of irregular frequency.