There are many different numeral systems, that is, writing systems for expressing numbers.
Numeral systems are classified here as to whether they use positional notation (also known as place-value notation), and further categorized by radix or base.
The common names are derived somewhat arbitrarily from a mix of Latin and Greek, in some cases including roots from both languages within a single name. There have been some proposals for standardisation.
The common names of the negative base numeral systems are formed using the prefix nega-, giving names such as:
Factorial number system {1, 2, 3, 4, 5, 6, ...}
Even double factorial number system {2, 4, 6, 8, 10, 12, ...}
Odd double factorial number system {1, 3, 5, 7, 9, 11, ...}
Primorial number system {2, 3, 5, 7, 11, 13, ...}
Fibonorial number system {1, 2, 3, 5, 8, 13, ...}
{60, 60, 24, 7} in timekeeping
{60, 60, 24, 30 (or 31 or 28 or 29), 12, 10, 10, 10} in timekeeping
(12, 20) traditional English monetary system (£sd)
(20, 18, 13) Maya timekeeping
Quote notation
Redundant binary representation
Hereditary base-n notation
Asymmetric numeral systems optimized for non-uniform probability distribution of symbols
Combinatorial number system
All known numeral systems developed before the Babylonian numerals are non-positional, as are many developed later, such as the Roman numerals. The French Cistercian monks created their own numeral system.