Decimal computer Decimal computer Decimal computers are computers which can represent numbers and addresses in decimal as well as providing instructions to operate on those numbers and addresses directly in decimal, without conversion to a pure binary representation. Some also had a variable wordlength, which enabled operations on numbers with a large number of digits. Early computers that were exclusively decimal include the ENIAC, IBM NORC, IBM 650, IBM 1620, IBM 7070. In these machines, the basic unit of data was the decimal digit, encoded in one of several schemes, including binary-coded decimal or BCD, bi-quinary, excess-3, and two-out-of-five code. Except for
Repeating decimal require the terminating decimal to be negative). For example, It follows that any repeating decimal with period "n", and "k" digits after the decimal point that do not belong to the repeating part, can be written as a (not necessarily reduced) fraction whose denominator is (10 − 1)10. Conversely the period of the repeating decimal of a fraction "c"/"d" will be (at most) the smallest number "n" such that 10 − 1 is divisible by "d". For example, the fraction 2/7 has "d" = 7, and the smallest "k" that makes 10 − 1 divisible by 7 is "k" =