F# does type inference like this: let x = 1; x is now an integer. Now you can't do printfn "%s" x; Only printfn "%i" x; So it has strong stati

F# does type inference like this: let x = 1; x is now an integer. Now you can't do printfn "%s" x; Only printfn "%i" x; So it has strong static typing, but most of the time you don't need to be explicit about them. It can even infer function types. If you use FSI (F# interactive( it will always print the signatures in between, so that it's really easy to explore interfaces.