If you are trying to show students or your children about fractions - a great site to check out is Mathplayground - specifically their fraction bars.
You can adjust the numerators and denominators (up to 16) and as you can see below each fraction shows a shaded section.
Great site to show like and unlike fractions. You can also remove the fractions so it will just show the amount and no fraction (just select on/off - upper left of screen).
Hope it helps!Brad