Absolute value function - F#

I’m starting to use talonvoice to program.

To get started, I’m copying the following function

let absVal num = if num < 0 then -num else num

[<EntryPoint>]
let main argv =    
    let negativeNumber = -23
    let absoluteValue = absVal negativeNumber
    
    printfn "%d" absoluteValue
    0