Civil ID

you can verify if the civil id number is correct or not by the following equation :

11 – Mod(( c1 * 2 ) + ( c2 * 1 ) + ( c3 * 6 ) + ( c4 * 3 ) + ( c5 * 7 ) +
( c6 * 9 ) + ( c7 * 10 ) + ( c8 * 5 ) + ( c9 * 8 ) + ( c10 * 4 ) + ( c11 * 2 )),11) = check digit

update:

one of the guys ask me to explain how the formula is working and I did on rtf format [link]

cid equation explanation