Messing around with F# trying to learn the basics. recreated the solution to problem 1 in a few moments thought I’d post it for kicks.

#light
open System
let l = [1 .. 999]
let  f = List.filter(fun i -> i % 3 = 0 || i % 5 = 0) l
let i = List.fold_left(+) 0 f
Console.WriteLine(i)
System.Console.ReadKey(true)

its nice to not have to check the final list for duplicates and that it was really easy to figure out how the filter command worked.