In-line Fraction with Horizontal Line

[Mark Greenberg]

Fellow list members, I have a problem for which I can only find  
difficult or unsatisfactory solutions, and I was hoping you might  
have some suggestions.

I am making a stack to teach students math -- linear equations, to be  
more precise.  When I display the y = mx + b form, the best I can do  
to show a fraction in the m position is something like y = 4/5x + 2.   
This is ambiguous because it isn't clear what should be taken as the  
divisor, 5 or 5x or 5x + 2.  The math teacher for whom I am making  
the game would prefer a horizontal division line instead of a slash.

So far this is what I've thought of and rejected:

Use fonts that have fractions built in as one character.  No, because  
they have too few for the range of possible slopes I want to generate.

Force the numerals around as subscripts and superscripts until it is  
clear what the fraction is.  Messy and probably won't lead to success.

Use inline images.  Need too many images to cover possible slopes.

Write it y = (4/5)x + 2.  This is mathematically acceptable, but not  
the way the students will see it elsewhere.

Use a different 2-line field that moves according to the location of  
the fraction.  Hmm.. maybe.

I could use some help on this one.

	TIA,
		Mark