Hi,

I tried like this already. But is not working. Check all test data. Thats real numbers taken from my family and friends. so check all of :

2607974450185
1109955455024
0805963450018
2611961455029
2411974450078


Vladimir

>Hi Vladimir,
>

>?2607974450185%13 && 0 - OK
>?2607974450181%13 && not 0 - Failed
>
>?MOD(2607974450185,13) && 0 - OK
>?MOD(2607974450181,13) && not 0 - Failed
>

>
>MartiJ
>
>>Hi,
>>
>>I have a field (soc. security number) that is 13 digits long and have this structure
>>
>>ddmmyyy45xxxc
>>
>>where
>>
>>dd - day of birth
>>mm - month of birth
>>yyy - year of birth without leading 1,2 (ex. 1965 - 965; 2002 = 002.....)
>>xxx - number from birth registry book (from 000-499 for mail 500-999 for female)
>>
>>c - control digit by mod13 rule
>>
>>how to calculate if entered value is corect by mod 13 rule.
>>
>>Few sample soc.security numbers
>>
>>2607974450185
>>1109955455024
>>0805963450018
>>2611961455029
>>2411974450078
>>
>>Thanks,
>>Vladimir