[Math Lair] Decimals

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A decimal, or decimal fraction, is a type of fraction whose denominator is a power of ten. Such a fraction is usually indicated by a dot, or decimal point, written to the right of a whole number. The fraction's denominator is not written and is implied by the number of decimal places. For example, 14.7 = 14710, 56.14 = 5614100, and 0.831 = 8311000.

Decimals can be classified as terminating or non-terminating. A terminating decimal ends at some point; it only has a finite number of (non-zero) decimal places. A decimal expression that does not end is a non-terminating decimal. For example, ½ = 0.5 is a terminating decimal, while ⅓ = 0.333333... is a non-terminating decimal. Non-terminating decimals can be further subdivided into repeating decimals, whose decimal expansion repeats after a while, and non-repeating decimals, whose decimal expansion never repeats. For example, 17 = 0.142857142857... is a repeating decimal, while π = 3.141592653589... is a non-repeating decimal. For repeating decimals, a bar or dots are used above the digits to denote the repeating portion of the decimal expression; for example, 17 can be written 0.142857.

Sources used (see bibliography page for titles corresponding to numbers): 64.