(I) ABC : CD = EF - * + (II) FDF + EG = AHD ----------------- (III) BB + FGA = AIJ (IV) (V) (VI) Solution: (IV.3) A = F + 1 (with carry) (IV.2) 10 = D + 1 (with carry) Therefore we get D = 9. (VI.1) J = F - 1 as F != 0 (III.1) B = J - A + 10 = 8 (I.1) C == 9 F (mod 10) => C + F == 10 F == 0 (mod 10) That is C = 10 - F (IV.1) 8 + F = C + 10 as C != 9 = D. Substitute C and we get F = 6 and back substitution gives C = 4, J = 5, A = 7. (II.1) G = 9 - F = 3 (III) I = 2 (I) E = 1 (II) H = 0 784 : 49 = 16 - * + 696 + 13 = 709 ----------------- 88 + 637 = 725 References: Bernhard Berchtold: Puzzle 9: Kryptogramm Januar 1999 http://www.mathematik.ch/puzzle/ Puzzle collection http://www.mathematik.ch/puzzle/puzzle9.php Puzzle http://www.mathematik.ch/puzzle/solut9.php Solution