Property	Value
Hex Value	`$12`
Categories	Catalog > R Math > Number
Localizations	FR: `arrondi(`

`round(`

Overview

Returns a number, expression, list, or matrix rounded to #decimals ( 9).

Availability: Token available everywhere.

Syntax

round(value[,#decimals])

Arguments

Name	Type	Optional
value
#decimals		Yes

Location

math, NUM, 2:round(

Description

round(value[,#decimals]) returns value rounded to #decimals decimal places. #decimals must be < 10. The default value for #decimals is 9. Also works on complex numbers, lists and matrices.

round(5.45,0)
     5
round(5.65,0)
     6
round(‾5.65,0)
     ‾6
round(π)-π
     4.102e-10
round(π,4)
     3.1416
round({1.5,2.4,3.8},0)
     {2,2,4}
round([[1.8,3.5,120.3][3,‾1,0.2]],0)
     [[2  4   120]
     [3  ‾1  0   ]]

Advanced Uses

Sometimes, round-off error will cause the result of an expression to be slightly off of the correct integer value — for example, a result may be 5.0000000013 instead of 5. If the error is small enough, it will not even be visible if you recall the variable on the home screen. However, this is enough to cause a ERR:DOMAIN error with commands such as sub( and Output(, which require their arguments to be integers.

The easiest way to fix this problem is by wrapping the different arguments in a round( instruction. For example, instead of:

Output(X,1,">")

Try:

Output(round(X,0),1,">")

The int( command will not work here because the round-off error may be negative, such as 4.9999999986 instead of 5, in which case the number will be rounded down to 4.

Error Conditions

ERR:DOMAIN if the number of places to round to is not an integer 0 through 9.

Source: parts of this page were written by the following TI|BD contributors: burr, CloudVariable, DarkerLine, GoVegan.

History

Calculator	OS Version	Description
TI-82	1.0	Added

Authors: Adrien Bertrand

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