SQL & PL/SQL

I need to validate the input of EAN-13 check digit
I use FORMS 4.5 & ORCALE DB 9i

2741023456884 (this is the scanned input)

2*1
7*3
4*1
1*3
0*1
2*3
3*1
4*3
5*1
6*3
8*1
8*3

2 + 21 + 4+3+0+6+3+12+5+18+8+24=106

106/10 = 10 remainder 6

10-6 =4 ( 4 matches the check digit in the above input last digit)

Note: if the remainder is 0 then 10 -0 = 10 and the check digit is the right most digit which is 0

Can any help me with this procedure, has any one did this before.

Thanks for you help in advance