How to convert the elements in a 2d string array to int and sum the rows?

[Leomar_2]

This is the code i have.
My vector is a 5x4 string vector which get test scores from a inputbox to get displayed in a listbox. I want to find the avergare in every test score so im trying to convert the elements from StudentsScores (my string 2d vector) to int so i can sum the rows and find the average but when i input "100, 100, 100, 100, 90, 90, 90, 90, 80, 80, 80, 80, 70, 70, 70, 70, 60, 60, 60, 60 to test if my code is working all i get if 60, 60, 60, 60, 60 in my average listbox.

 For Index = 0 To 4
            For InnerIndex = 0 To 3

                TempTotal = TempTotal + CInt(StudentsScores(Index, InnerIndex))

            Next
            'TempTotal /= 4
            lstAvg.Items.Add(TempTotal.ToString())
        Next