Is there a name for numbers between 0 and 1? In the world of competitive esports, players often discuss kill/death ratios, where higher is better. My friends sometimes call a poor ratio, like 1 kill to 4 deaths, as 'negative', but that's not quite right. Is there another word to describe values between 0.0 and 1.0, vs values larger than 1.0?
 A: It can be called the Unit Interval

In mathematics, the unit interval is the closed interval [0,1], that is, the set of all real numbers that are greater than or equal to 0 and less than or equal to 1. It is often denoted I (capital letter I). In addition to its role in real analysis, the unit interval is used to study homotopy theory in the field of topology.

A: Since you seem to be primarily interested in rational numbers, a good candidate is proper fraction.
A: Your friends aren't wrong for describing a 1kill, 4 deaths score as negative. They are simply using a different metric, kills-deaths, instead of what you're using, kills/deaths. Both are useful in different scenarios and you should aim to go positive with an improper fraction for a kdr.
A: A simple mathematical way of describing this is by using the log function.
A number between 0 and 1 has a negative log and a number larger than 1 has a positive log...
So "negative log" and "positive log" could be a way of referring to this.
Note that with this notation, your kills/deaths ration becomes
$$
\log (\frac{kills}{deaths})=\log(kills)- \log (deaths)
$$
A: I'm not sure that I would use a term from mathematics.  You might consider using a term like "subpar", where "par" would be $1:1$, as in "One kill to four deaths is a subpar kill/death ratio."
