var app = new Microsoft.Office.Interop.Access.Application();
app.OpenCurrentDatabase(@"C:\Users\Public\Database1.accdb");

// A VBA Module in the opened database contains:
//
// Public Function AddTenFunction(in_value As Long) As Long
//     AddTenFunction = in_value + 10
// End Function
//
int fnResult = app.Run("AddTenFunction", 4);

app.Quit();
Console.WriteLine(fnResult);