2 fraction circles
2 fraction circles with drag-able totals
small: 2 fraction circles
small: 2 fraction circles with drag-able totals
All in one: all of the above on the same page

2 fraction bars
2 fraction bars with drag-able totals
small: 2 fraction bars
small: 2 fraction bars with drag-able totals
All in one: all of the above on the same page

A fraction modeled as a subset of a discrete set.
Small: fraction modeled as a subset of a discrete set
Both: both of the above on the same page

2 fractions modeled as subsets of rectangles:
2 fractions modeled as subsets of squares
All in one: all of the above on a single web page.