FIZZBUZZ
HOW IT WORKS: counting from 1-100, replace all multiples of 3 with fizz, all multiples of 5 as buzz, and multiples of both 3 and 5 as fizzbuzz.
1, 2, fizz, 4, buzz, fizz, 7, 8, fizz, buzz, 11, fizz, 13, 14, fizzbuzz, 16, 17, fizz, 19, buzz, fizz, 22, 23, fizz, buzz, 26, fizz, 28, 29, fizzbuzz, 31, 32, fizz, 34, buzz, fizz, 37, 38, fizz, buzz, 41, fizz, 43, 44, fizzbuzz, 46, 47, fizz, 49, buzz, fizz, 52, 53, fizz, buzz, 56, fizz, 58, 59, fizzbuzz, 61, 62, fizz, 64, buzz, fizz, 67, 68, fizz, buzz, 71, fizz, 73, 74, fizzbuzz, 76, 77, fizz, 79, buzz, fizz, 82, 83, fizz, buzz, 86, fizz, 88, 89, fizzbuzz, 91, 92, fizz, 94, buzz, fizz, 97, 98, fizz, buzz.