An interior decorator bought 12 1/2 yards of material to make drapes. he used 8 2/3 yards on one pair of drapes. how much material does he have left?

3.9 yards is the answer 

Ok, so this is a subtraction problem with fractions.  The first step is to write the equation you need to make.

12 1/2  -  8 2/3

Next would be to change the mixed fractions to improper fractions.

25/2  -  26/3

Now, we need to find a common denomintor, since we can't just subtract like it is now.  The Lowest Common Denominator would be 6 because 2*3 = 6.  So we need to multiply the numerator and the denominator of both fractions, so that they will have the same denominator.

3( 25/2 )  -  2( 26/3 )

75/6  -  52/6

Now we just subtract the numerators and leave that new answer over the same denominator.

75/6  -  52/6  =  23/6

If it asks to simplify into fraction, we can put it as,

3 5/6