8137225 and whats the letter?

If my IC number is 8137225, what will be my last letter?

I'll take,

8 x 2 = 16
1 x 7 = 7
3 x 6 = 18
7 x 5 = 35
2 x 4 = 8
2 x 3 = 6
5 x 2 = 10

I shall sum up the products,
16+7+18+35+8+6+10= 100

Next I will divide the sum by 11 to obtain a remainder value,

100/11 = 9 r 1

Now with this remainder of 1, I will refer to the following reference,

10=A
9=B
8=C
7=D
6=E
5=F
4=G
3=H
2=I
1=Z
0=J

The last letter of my IC is Z...

Credit goes to Ngiam Shih Tung for showing us all the algorithm which the government will charge S$200 for use. Now its yours for free. So far it works only for S-series IC numbers.