is it possible to determine parts of a string inside a cell and make an argument?

here is my code, explanation below:

Select Case cells(1,1).value
    Case "125/240"
        Part_Number = "125"
    Case "100/380"
        Part_Number = "100"
    Case "80/250"
        Part_Number = "080"
    Case "63/125"
        Part_Number = "063"
    ' hundreds of other cases are written below
end select

I need a more efficent way of getting the part number. cells(1,1) is a cell where the system inputs a catalogue number for a certain unit. The part number is the number before the "/". I need to extract the part number from cell(1,1). I also need to add the zeroes for example 63/125 would be "065" and 80/250 would be "080"


So i need an argument that's something like this:

Get the number before the "/" inside the string and label it as the Part_Number.
Let X be the number of digits after "/"
Let Y be the number of digits before "/"
X-Y = number of Zeroes to add before the part number


Is VBA capable of doing this? It seems impossible =\...

May be try like this...

Sub GetPartOfTheNumber()

With Cells(1, 1)
    Part_Number = Format(Left(.Value, InStr(.Value, "/") - 1), "000")
End With

MsgBox Part_Number

End Sub