I almost overlooked this article because I got turned off by the opening description in base 10 The article talks about the last digit: That's also the remaind

I almost overlooked this article because I got turned off by the opening description in base 10 The article talks about the last digit: That's also the remainder upon dividing by 10, a perfectly sensible thing to discuss. Similarly what it discusses in base 3 is the last digit, the remainder upon dividing by 3. Properties of numbers, particularly primes, modulo other numbers have been much studied by number theorists.