Imports System
Public Module Module1
Public Sub Main()
Dim ISBN(13) As Integer
Dim Total As Integer = 0
Dim CheckDigit As Integer
For i = 1 to 12
Console.WriteLine("Please enter the number" & i)
ISBN(i) = Console.ReadLine()
Next
If i MOD 2 = 1 Then
Total = Total + ISBN(i)
Else
Total = Total + (ISBN(i) * 3)
End If
If Total MOD 10 = 0 then
CheckDigit = 0
CheckDigit = 10 - Total MOD 10
End if
Console.WriteLine(CheckDigit)
End Sub
End Module
