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	Topics Significand Topic Home The significand (also coefficientCoefficient In mathematics, a coefficient is a constant multiplicative factor of a certain object.... or mantissaMantissa Mantissa can mean:* The "fraction part" of the result of a logarithm.... ) is the part of a floating-point numberFloating point Floating-point is a means of representing real numbers in terms of digits or bits in a computer or calculator, similar to ho... that contains its significant digits. Depending on the interpretation of the exponent, the significand may be considered to be an integerInteger The integers consist of the positive natural numbers , their negatives and the number zero.... or a fractionFraction (mathematics) In mathematics, a fraction is a way of expressing a quantity based on an amount that is divided into a number of equal-sized... . Examples For example, the number 123.45 can be represented as a decimalDecimal The decimal numeral system has ten as its base.... floating-point number with integer significand 12345 and exponent −2. Its value is given by the arithmetic: 12345 × 10⁻² This same value could also be represented in normalized formScientific notation Scientific notation is a notation for writing numbers that is often used by scientists and mathematicians to make it easier ... with the fractional (non-integer) coefficient 1.2345 and exponent +2: 1.2345 × 10⁺² or in the format given by the Language Independent Arithmetic standard and several programming language standards (including Ada, C, FortranFortran Summary FORTRAN is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation a... and Modula-2Modula-2 Modula-2 is a computer programming language invented by Niklaus Wirth at ETH around 1978, as a successor to Modula, an inter... ) as: .12345 × 10⁺³ Significands and the hidden bit In describing binaryBinary numeral system The binary numeral system represents numeric values using two symbols, typically 0 and 1.... floating-point types, the significand is characterised by a certain width in bitBit A bit refers to a digit in the binary numeral system .... s (binary digits). Because the most significant bit is always 1 for normal numberNormal number (computing) In computing, a normal number is a non-zero number in a floating-point representation which is within the balanced range sup... s, this bit is typically not stored and is called the "hidden bit". Depending on the context, the hidden bit may or may not be counted in describing the width of the significand. For example, the same IEEE 754 double precisionDouble precision In computing, double precision is a computer numbering format that occupies two storage locations in computer memory at addr... format is commonly described either as having a 53-bit significand/mantissa (including the hidden bit) or as having a 52-bit significand/mantissa (not including the hidden bit). Use of "mantissa" main article: mantissaMantissa Mantissa can mean* The "fraction part" of the result of a logarithm.... The original word used in American English to describe the coefficient of floating-point numbers in computer hardware, later called the significand, seems to have been mantissa (see Burks et al., below), and as of 2005 this usage remains common in computing and among computer scientistsComputer science Computer science, or computing science, is the study of the theoretical foundations of information and computation and... . However, this use of mantissa is discouraged by the IEEE floating-point standardIEEE floating-point standard The IEEE Standard for Binary Floating-Point Arithmetic is the most widely-used standard for floating-point computation, and... committee and by some professionals such as William KahanWilliam Kahan William Morton Kahan is a mathematician and computer scientist whose main area of contribution has been numerical analysis.... and Donald KnuthDonald Knuth Donald Ervin Knuth is a renowned computer scientist and at Stanford University.... , because it conflicts with the pre-existing usage of mantissa for the fractional part of a logarithmLogarithm The logarithm is the mathematical operation that is the inverse of exponentiation .... (see also common logarithmCommon logarithm In mathematics, the common logarithm is the logarithm with base 10.... ). The older meaning of mantissa is related to the IEEE's significand in that the fractional part of a logarithm is the logarithm of the significand for the same base, plus a constant depending on the normalization. (The integer part of the logarithm requires no such manipulation to relate to the floating-point exponent.) The logarithmic meaning of mantissa dates to the 18th century (according to the OEDOxford English Dictionary *The Oxford English Dictionary* is a dictionary published by the Oxford University Press , and is generally regarded as t... ), from its general English meaning (now archaic) of "minor addition", which stemmed from the LatinLatin Latin is an ancient Indo-European language originally spoken in Latium, the region immediately surrounding Rome.... word for "makeweight" (which in turn may have come from EtruscanEtruscan language Etruscan was a language spoken and written in the ancient region of Etruria and in parts of what are now Lombardy, Veneto, ... ). Significand is a 20th century neologismNeologism Overview A neologism is a word, term, or phrase which has been recently created — often to apply to new concepts, or to reshape... . Unfortunately, while significand was apparently coined on the model of earlier words like multiplicand, it is not etymologically correct since it means "that which is to be signified" rather than that which is significant.