DecimalToFraction

DecimalToFraction[ d ] returns the simplest fraction with the same value as a decimal number.

Usages

`DecimalToFraction[ d ]`

DecimalToFraction[ d ] writes the decimal number d as a fraction with exactly the same value, simplified as far as possible. d can have at most 10 decimals.

Example	in	out
`1.25 = 5/4`.	`DecimalToFraction[ 1.25 ]`	`5/4`
A negative number.	`DecimalToFraction[ -0.75 ]`	`-3/4`
The value stays exactly the same: `0.333333` is not `1/3`.	`DecimalToFraction[ 0.333333 ]`	`333333/1000000`
A script variable.	`x := 3.14 r := DecimalToFraction[x]`	`r = 157/50`

Details

Integers give a fraction with denominator 1: DecimalToFraction[ 4 ] returns 4/1 and DecimalToFraction[ 2.0 ] returns 2/1.
More than 10 decimals: DecimalToFraction[ 0.12345678901 ] is left unevaluated.
Numbers without a finite decimal representation, such as Pi, are left unevaluated.

Invalid input	Result
`DecimalToFraction[ 1/3 ]`, `DecimalToFraction[ x ]`	Error: the argument should be a decimal number
`DecimalToFraction[ {0.5, 0.25} ]`	Error: the argument should be a decimal number. Use `Map` for a list.
`DecimalToFraction[ 0.5, 1 ]`	Error: the number of arguments should be 1

See also: Numerator, Denominator, Numerical