I had a couple of tasks on Numbers. In the shots with the largest swarms, we used a traditional Maya particle instancer workflow. I wrote a couple of custom dynamics fields to help to achieve the flocking and following behavior.

For shots with fewer numbers we used basic hand-animated geometry. To accelerate the process we duplicated large groups of numbers and offset their animation in time. I wrote a MEL script which allowed us to animate the geometry without worrying about the numbers themselves. The script would walk the scene and replaced the numerals with randomly selected numbers. The distribution was user-controllable, so if a shot felt like it had say, too many 4's in it, an artist could tweak the distribution so that there were fewer.