Creating a User-Defined Range for Formulas

Hey Folks,

I'm trying to generate an InputBox that allows the user to define the variable that will determine the range for the values spit out by a Macro.

inputvalue = Application.InputBox(prompt:="Please enter a number.", Title:="Enter a Number", Type:=1)
If inputvalue = ("1") Then Range = ("f2")
If inputvalue = ("2") Then Range = ("f2:f3")
If inputvalue = ("3") Then Range = ("f2:f4")
If inputvalue = ("4") Then Range = ("f2:f5")
If inputvalue = ("5") Then Range = ("f2:f6")
If inputvalue = ("6") Then Range = ("f2:f7")
If inputvalue = ("7") Then Range = ("f2:f8")
If inputvalue = ("8") Then Range = ("f2:f9")
If inputvalue = ("9") Then Range = ("f2:f10")
End If
     inputvalue= ("0")

I keep getting an argument not optional error, and I'm unsure as to what it means here. I'm relatively new at this, and could use any help!

Thanks folks,
NP