I would like to know if there's a name for "digits after the decimal point" (in only one or two words). For instance in french these digits are called "d├ęcimales".

I've found "decimal places", but I am not sure it is synonym, for instance, considering the number 7.9362, would it be correct to say that its decimal places are 9, 3, 6 and 2?

EDIT: several answers are useful, so it's not easy to choose only one...

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    The collocation decimal places is usually only used in expressions like This value is accurate to four decimal places - meaning the (first) four digits after the decimal point have been specified and are known to be correct. You wouldn't call one of the individual digits a "decimal place". Although it's evocative of a completely different way of writing non-integers, I'd still be inclined to say that any digits after the decimal point are (or represent) the fractional part. But accurate to four significant digits says nothing about where the decimal point might be. – FumbleFingers Reinstate Monica Sep 12 '17 at 15:04
  • You could say, for example, "What number is in the second decimal place?" That makes perfect sense. Also, each position does have a name - "tenths place", "hundredths place", "thousandths place", and so on. But I doubt those descriptions would be used by an actual mathematician. – user428517 Sep 12 '17 at 17:25
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    Technically: digits. Colloquially? decimals is acceptable. Only mathematicians and pedants will correct you on it. E.g., How many decimals of Pi do you people remember by heart? – Mazura Sep 12 '17 at 22:38
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    @Mazura, decimals is unambiguous, whereas digits is not. – SwiftsNamesake Sep 12 '17 at 22:50
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    @SwiftsNamesake, I wouldn't say unambiguous. When I hear "decimal" I think of base-10 digits as opposed to binary or hexadecimal. Like "102.3" has 4 decimal digits. "dead.beef" has 8 hexadecimal digits. :) – JoL Sep 13 '17 at 21:45

You can call the digits to the left of the decimal point integer digits or integral digits and those to the right of the decimal point fraction digits or fractional digits.

Java I/O, Harold (2006):

For instance, in the number 31.415, there are two integer digits and three fraction digits.

Microprocessor Engineering, Holdsworth (2013):

...where n is the number of integral digits and m the number of fractional digits.

Perhaps these terms are not well-established, but they are used in the literature and will be understood in the appropriate context.

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    If your context is math. If your context is just everyday speech, these might be a bit confusing. – Azor Ahai -- he him Sep 12 '17 at 20:30
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    I chose your answer because it also works with my example: considering the number 7.9362, it is then correct to say that its fraction digits are 9, 3, 6 and 2 – zezollo Sep 13 '17 at 11:21
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    @Azor-Ahai The only context I can think of in everyday life where you'd want a name for the digits before versus after the decimal point of a number would be if that number was a price. And in that case, you'd just refer to the "number of pounds/dollars/euros" versus "number of pence/cents". In any other case, the fact that you're talking about the digits in a number means you're almost certainly talking about mathematics. – David Richerby Sep 13 '17 at 12:08
  • @DavidRicherby I mean if you're talking about "mathematics," sure, but if you're doing some back-of-the-napkin math, the might be less understandable. – Azor Ahai -- he him Sep 13 '17 at 22:22
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    @Azor-Ahai What term would you suggest to apply to this mathematical situation without using formal mathematical terminology? The common way of describing it would be to say "the numbers to the right [or left] of the decimal point", and I fear any specific term beyond this could be rejected as "mathematics" using an argument similar to your own. – Darren Ringer Sep 14 '17 at 16:49

Fractional part is both used in mathematics and other fields where such things are discussed, and easily understood by lay readers.

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  • This could also be non decimal fractions like 3/4 so not fully descriptive. – KalleMP Sep 12 '17 at 20:52
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    The same objection (about fractions that are not expressed in decimal form) applies to the definition of mantissa that was offered in another answer. – David K Sep 13 '17 at 0:47
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    @KalleMP "What's the name of the Speaker of the US House of Representatives?" "Paul Ryan." "There could also be other people called Paul Ryan, so not fully descriptive." The question asks for the name of a particular thing; this answer gives that name. So what if that name could also apply to other things? – David Richerby Sep 13 '17 at 12:05
  • @KalleMP In mathematics and computing, a radix point is the symbol used in numerical representations to separate the integer part of a number (to the left of the radix point) from its fractional part (to the right of the radix point). In base 10 notation, the radix point is more commonly called the decimal point. Similarly, the term "binary point" is used for base 2. – q-l-p May 25 '18 at 21:48
  • Can I say "a number that doesn't include a fractional part"? – x-yuri May 22 '19 at 13:16

The fractional part of a number is known as the Mantissa.

The mantissa is defined as the positive fractional part of a real number.

Your suggestion of decimal places is usually used to specify a number of digits that must follow the decimal point. The term mantissa makes no such restriction. It defines all the digits after the decimal point.

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    Note though that Mantissa is not a commonly used word outside of mathematics. – eques Sep 12 '17 at 15:26
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    Mantissa is often used only with logarithms. Confusingly in programming and computer science it's often used of the entire significand of a number expressed in scientific notation. – Jon Hanna Sep 12 '17 at 16:39
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    @JonHanna That's because most floating-point representations use an implicit radix point. – chrylis -cautiouslyoptimistic- Sep 12 '17 at 16:54
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    this Wikipedia article cites Donald Knuth's The Art of Computer Programming with "it is an abuse of terminology to call the fraction part a mantissa, since this concept has quite a different meaning in connection with logarithms" – dlatikay Sep 12 '17 at 19:06
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    Have to agree with @Jon Hanna - I have always know the "mantissa" to be the fractional part of base-10 logarithms - whilst the integral is called the "characteristic". It would be confusing I think to refer to the fractional part of any number as the "mantissa" – Fraser Sep 12 '17 at 19:19

They're called decimals. This is a term everyone will understand.

If a billion decimals of pi were printed in ordinary type, they would stretch from New York City to the middle of Kansas.

Panic in Level 4: Cannibals, Killer Viruses, and Other Journeys to the Edge of Science by Richard Preston

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    Just wondering why decimals of pi are special - surely a string of a billion as would have the same effect? – boboquack Sep 14 '17 at 3:11
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    It is an irrational number. @boboquack – ferit Sep 14 '17 at 4:46
  • Would it be correct to say that '4' is one decimal of '9.046'? – zezollo Sep 14 '17 at 5:02
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    @Saibot I know that, but aaaaaa takes up the same amount of space as 3.14159 or anyone or ^%&$*( – boboquack Sep 14 '17 at 5:02
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    If all the decimals of pi (or any other number) were printed in ordinary type, the universe would run out of space and energy. Not so special after all. :) – Masked Man Sep 14 '17 at 16:26

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