Finding an average value using integer arrays - arrays

Question

In my program I have designed it so that it reads from a file, parses the file for any integers and saves them to a sorted list. From that list I have then created three arrays which would each hold different values based off the values in the list except the values would go up by 1 for each array so:
Example Values:
array 1 will hold the regular values e.g. - 2,3,4,5
array 2 will hold the regular values (+1) - 3,4,5,6
array 3 will hold the regular values (+2) - 4,5,6,7
2,3,4 = 1st user's score
3,4,5 = 2nd user's score
4,5,6 = 3rd user's score
From this I now want to add these arrays together and divide by 3 to get the average results and then save and join the values with their corresponding user, however am not sure if I can add the arrays directly.
This is the code I have so far:
Dim basenum As New System.Collections.Generic.List(Of Integer)
Dim num As String
num = Regex.Replace(line, "\D+", "")
For Each lin As String In num
basenum.Add(Convert.ToInt32(lin))
Next
basenum.Sort()
basenum.Reverse()
For Each element As Integer In basenum
Console.WriteLine(element)
Next
Dim number1() As Integer
Dim number2() As Integer
Dim number3() As Integer
number1 = basenum.ToArray
For Each element As Integer In number1
Console.WriteLine(element)
Next
number2 = basenum.ToArray 'insert 2nd numbers into second array
For Each element As Integer In number2
element += 1
Console.WriteLine(element)
Next
number3 = basenum.ToArray 'insert 3rd numbers into third array
For Each element As Integer In number3
element += 2
Console.WriteLine(element)
Next
The numbers go into the arrays fine however am not sure how I can add the arrays together and calculate the average.
Any help would be appreciated guys :)