Decimal numbers that may be expressed as a fraction, the denominator of which is a power of ten. For example, the numerals formula_5 represent the fractions , , . More generally, a decimal with digits after the separator represents the fraction with denominator , whose numerator is the integer obtained by removing the separator. Expressed as a fully reduced fraction, the decimal numbers are those, whose denominator is a product of a power of 2 by a power of 5. Thus the smallest denominators of decimal numbers are The "integer part", or "integral part" of a decimal is the integer written
Repeating decimal divided by the one represented by "n" digits 9. For example, If the repeating decimal is as above, except that there are "k" (extra) digits 0 between the decimal point and the repeating "n"-digit block, then one can simply add "k" digits 0 after the "n" digits 9 of the denominator (and, as before, the fraction may subsequently be simplified). For example, Any repeating decimal not of the form described above can be written as a sum of a terminating decimal and a repeating decimal of one of the two above types (actually the first type suffices, but that could