how this function will be work

Hi,

 function that checks civil id . The rule is : 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

 how this function will be work I have one Textbox1.Text and one Button1 now when i click on button it should check through the above formula and give me message is it correct digit in my Textbox1.Text or wrong digit as per formula.

 Regards,
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