Is this a valid code?
2 1 5 8 7 2 9 4 6
2*7+1*3+5*9+8*7+7*3+2*9+9*7+4*3+6*9=
4+3+5+6+1+8+3+2+4 = 6 (mod 10) so this is not a valid code--it does not have a correct check digit.