*“FRACTRAN is a simple theoretical programming language for arithmetic that has none of the defects described above.*”

— The FRACTRAN User Manual

## What is FRACTRAN?

FRACTRAN is a very simple Turing-complete programming language invented by John Conway. The program consists of a list of fractions. The current state of the prgram is a positive integer. Each step, the state is multiplied by the first fraction such that the result is a whole number.(Using mouse to drag around a fraction to move/re-order, or drag/drop to garbage/delete bin to remove it.)

Or, load a pre-defined program:

Or, load a program from a file:

(Please input a integer value for N below)

Save n

## A note about file formats

The starting index is separated from the program by a semicolon. The starting index may be left blank. The program’s fractions are separated by commas, and the numerator and denominator are separated by a slash (ex.`144/77`

). Save it as a `.frac`

, `.fc`

, `.fractran`

, or `.txt`

file.