Editing Round number (section)

{{Short description|Integer ending in zeroes}}
{{Use dmy dates|date=August 2021}}
{{more citations needed|date=May 2012}}

A '''round number''' is an [[integer]] that ends with one or more "[[0 (number)|0]]"s (zero-digit) in a given [[Radix|base]].<ref>Sadock, J. M. (1977). Truth and approximation. ''Berkeley Linguistics Society Papers'' 3: 430–439.</ref> So, 590 is rounder than 592, but 590 is less round than 600. In both technical and informal language, a round number is often interpreted to stand for a value or values near to the nominal value expressed. For instance, a round number such as 600 might be used to refer to a value whose magnitude is actually 592, because the actual value is more cumbersome to express exactly. Likewise, a round number may refer to a [[Interval (mathematics)|range]] of values near the nominal value that expresses imprecision about a quantity.<ref name=Ferson-etal-2015>Ferson, S., J. O'Rawe, A. Antonenko, J. Siegrist, J. Mickley, C. Luhmann, K. Sentz, A. Finkel (2015). Natural language of uncertainty: numeric hedge words. ''International Journal of Approximate Reasoning'' 57: 19–39.</ref> Thus, a value reported as 600 might actually represent any value near 600, possibly as low as 550 or as high as 649, all of which would ''[[rounding|round]]'' to 600.

In [[decimal notation]], a number ending in the digit "5" is also considered more round than one ending in another non-zero digit (but less round than any which ends with "0").<ref name=Ferson-etal-2015 /><ref>de Lusignan, S., J. Belsey, N. Hague and B. Dzregah (2004). End-digit preference in blood pressure recordings of patients with ischaemic heart disease in primary care. ''Journal of Human Hypertension'' 18: 261–265.</ref> For example, the number 25 tends to be seen as more round than 24. Thus someone might say, upon turning 45, that their age is more round than when they turn 44 or 46. These notions of roundness are also often applied to [[Decimal#Decimal fractions|non-integer numbers]]; so, in any given base, 2.3 is rounder than 2.297, because 2.3 can be written as 2.300. Thus, a number with fewer digits which are not trailing "0"s is considered to be rounder than others of the same or greater precision.

Numbers can also be considered "round" in [[numeral system|numbering systems]] other than [[decimal]] (base 10). For example, the number 1024 would not be considered round in decimal, but the same number ends with a zero in several other numbering systems including [[binary numeral system|binary]] (base 2: 10000000000), [[octal]] (base 8: 2000), and [[hexadecimal]] (base 16: 400). The previous discussion about the digit "5" generalizes to the digit representing ''b''/2 for base-''b'' notation, if ''b'' is [[parity (mathematics)|even]].