Question 66616
Subtract and write in simplest form:
You were right about the numerator, but the denominator doesn't change.  Think of the numerator (top) as being the number of slices of pie that you have.  Think of the denominator (bottom) as being the number of slices that the pie was cut into. If the pie was cut z (some unknown quantity) times and I had 12 slices and gave you 10 slices, I'd have 2 out of z slices left.
{{{12/z-10/z}}}
{{{(12-10)/z}}}
{{{highlight(2/z)}}}
Happy Calculating!!!