Math Based Question?

Question

I'm in liberal Arts Math in college and I need help with real-life applications. I have a few in mind but I wanted more ideas. We're studying groups and modulars systems and I need at least three more:

Modular Systems:
3 examples of modular systems (i.e. things that happen periodically and are time accustomed)

Groups:
Thngs that naturally occur in groups.


Any help is appreciated.

Answer 1

Size (or time) of apple crops.
Number of birds (or start date) migrating in the fall.
Number of hurricanes in September, or distribution of hurricanes during the year.
Number of consecutive losses for NY Knicks.