anchor.diff:  
     [<Test>]
     let ``sign float`` () = <@ sign -1.0 @> |> check -1
  +
  +  [<Test>]
  +  let ``sign decimal`` () = <@ sign -1.0M @> |> check -1
   
     [<Test>]
     let ``sin float`` () = <@ sin 0.5 @> |> check (sin 0.5)
  
positive.code: 
    [<Test>]
    let ``abs float`` () = <@ abs -1.0 @> |> check 1.0
  
    [<Test>]
    let ``acos float`` () = <@ acos 0.5 @> |> check (acos 0.5)
  
negative.code:   let ``ceil float`` () = <@ ceil 1.5 @> |> check 2.0
  
    [<Test>]
    let ``ceil decimal`` () = <@ ceil 1.5M @> |> check 2.0M
  
    [<Test>]
    let ``cos float`` () = <@ cos 0.5 @> |> check (cos 0.5)
  
    [<Test>]
  