> Coding modulus from scratch with just + - / * is a fun little challenge in its own right, but it'll probably take you longer than 10 minutes to write it correctly and solve fizzbuzz with it.

I've seen numerous people fail on FizzBuzz despite supposedly being senior engineers.

None of them failed because they didn't know the modulo operator. For one thing, it's actually pretty easy to solve even without modulo.

If someone doesn't know modulo, I'll happily explain it.

More commonly, people struggle with even basic things like setting up a loop at all.