Step 1: Set up a two-row matrix, labeled 1 through 22 (or up to 26);
1 being the most significant position in the matrix (i.e., the right-most position).
Starting from the least significant position of the matrix (position 22 up to 26),
copy each digit of the PIC all the way to position 2 (excluding the position of the check digit
shown in the example below by a "?").
Pos 22 21 20 19 18 17 16 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01
PIC 9 2 1 2 3 9 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 ?
Step 2: Starting from position 2 of the matrix, add the values (shaded) in the even-numbered boxes.
For the example: 7+5+3+1+7+5+3+1+3+1+9 = 45
Step 3: Multiply the result of step 2 by 3. For the example: 45 x 3 = 135
Step 4: Starting from position 3 of the matrix, add up the values (shaded) in the odd-numbered boxes.
For the example: 6+4+2+8+6+4+2+9+2+2 = 45
Step 5: Add up the results for steps 3 and 4. For the example: 135+ 45 = 180
Step 6: The check digit is the smallest number which, when added to the result obtained through step 5,
gives a number that is a multiple of 10.
For example: 180 + X = 180; X = 0
NOTE: The dimension of the matrix (the number of cells) will vary depending on the length of the
Sequential Package ID. In this example, the Sequential Package ID is eight digits long (00000001),
requiring a matrix with 22 cells (including the cell for the check digit).