After 1 hour,Jon had finished 5/9 of a long-distance race, and Ling had finished 7/9 of it. At that time, who had finished a greater fraction of the race, and by how munch.
If you cut a cake into 9 pieces, which is more -- 5 of those pieces or 7 of those pieces?
7/9 - 5/9 = 2/9