UPC11Text = "02636267000"
DigitsList = {0, 2, 6, 3, 6, 2, 6, 7, 0, 0, 0}
OddSum = Sum of odd-positioned digits = 0 + 6 + 6 + 6 + 0 = 18
EvenSum = Sum of even-positioned digits = 2 + 3 + 2 + 7 + 0 + 0 = 14
TotalSum = OddSum * 3 + EvenSum = 18 * 3 + 14 = 68
Mod10 = TotalSum Mod 10 = 68 Mod 10 = 8
CheckDigit = If Mod10 = 0 then 0 else 10 - Mod10 = 10 - 8 = 2