Comment by Findecanor

An alternative numerical notation uses decimals but marks which digits at the end that are repeating. With enough digits, this format can represent all rational numbers that can be written in the standard numerator/denominator format.

It does of course work with base 2 and exponents as well so you could still be using floating-point format, only with additional meta-data indicating the repeating range. When a result degenerates into a number that can't fit within the number of digits, you would be left with a regular floating-point number.

I'd want to write a simple calculator that uses this numerical format but I have only been able to find algorithms for addition and subtraction. Every description I've found of the format has converted to the regular numerator/denominator form before multiplication and division.