How to get the Last Alphabet in NRIC?

S7654321F

Example:

7654321

(7 x 2) + (6 x 7) + (5 x 6) + (4 x 5) + (3 x 4) + (2 x 3) + (1 x 2)

= 14 + 42 + 30 + 20 + 12 + 6 + 2

= 126

Mod 11 of 126

= 126 / 11

= 11.4545

= 11.4545 – 11

= 0.4545 x 11

= 5

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