This is FizzBuzz:

1. Output the numbers from 1 to 100

2. If the number is a multiple of 3, write Fizz instead of the number

3. If the number is a multiple of 5, write Buzz instead of the number

4. If the number is a multiple of 3 and 5, write FizzBuzz instead of the number

Does that really sound like something requiring special practice and preparation? Assuming a decent interviewer would help out with the modulo operator if that was unfamiliar