Decimal and, only the best mathematicians were able to multiply or divide large numbers. These difficulties were completely solved with the introduction of the Hindu–Arabic numeral system for representing integers. This system has been extended to represent some non-integer numbers, called "decimal fractions" or "decimal numbers" for forming the "decimal numeral system". For writing numbers, the decimal system uses ten decimal digits, a decimal mark, and, for negative numbers, a minus sign "−". The decimal digits are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9; the decimal separator is the dot "" in many countries (including English speaking ones),
Repeating decimal some other properties of repetends, see also. Various features of repeating decimals extend to the representation of numbers in all other integer bases, not just base 10: For example, in duodecimal, 1/2 = 0.6, 1/3 = 0.4, 1/4 = 0.3 and 1/6 = 0.2 all terminate; 1/5 = 0.2497 repeats with period 4, in contrast with the equivalent decimal expansion of 0.2; 1/7 = 0.186ᘔ35 has period 6 in duodecimal, just as it does in decimal. If "b" is an integer base and "k" is an integer, For example 1/7 in duodecimal: Which is 0.186ᘔ35 (base 12). Note that 10