So there is a system of writing mixed numbers (that is, a combination of whole number and fraction, used instead of an “improper” fraction) used in cases where typing vulgar fractions (e.g. ½) is difficult or impossible, wherein the whole number is joined to the fraction (written with full-size numbers separated by a forward slash) by a hyphen. For example, the quantity 1.5 is written as 1-1/2 when 1½ is desired but the ½ character is unavailable.
I think it is fair to say that this is a stupid, ambiguous, and terrible practice. Most would read 1-1/2 as 1 − ½, that is the expression one minus one-half. But nevertheless, I have seen it used; cf. this RPG Stack Exchange question about it, since the Pathfinder Roleplaying Game System uses it (and they inherited it from Dungeons & Dragons, at least the System Reference Document for the 3.5 edition of the game).
Does anyone know where this notation came from, who its proponents are, etc.? I realize this is a rather unusual question for this site, but I feel that the Stack Exchange system is ideal for this sort of question and that this site seems like the most likely Stack to include experts who might know the answer to this.