I have written this function in Scala to calculate the fibonacci number given a particular index n: def fibonacci(n: Long): Long = { if(n <= 1) n else fibonacci(n - 1) + fibonacci(n - 2) } However it is not efficient when calculating with large indexes. Therefore I need to implement a function using a tuple and this function should return two consecutive values as the result. Can somebody give me any hints about this? I have never used Scala before. Thanks!