Solution for IX and X Does your solution look like this: package main func roman(number int) string { result := "" if number >= 10 { result = "X" number = number - 10 } if number >= 9 { result = "IX" number = number - 9 } if number >= 5 { result = "V" number = number - 5 } if number == 4 { result = "IV" number = number - 4 } for i := 0; i < number; i++ { result += "I" } return result } Do your tests look like this?