(I) ABC * DE = CFGH + * - (II) JDHJ + DGC = JGKK ---------------------- (III) JEDK + EBAH = FAGH (IV) (V) (VI) Solution: From (III.1) or (VI.1) follows K=0. Now collect the other equations of the last digits and other digits at the positions, where the state of the carry is known (II.1) J + C == 0 (II.2) H + G + 1 == 0 with carry (II.3) 2D + 1 == G with carry (III.2) D + A == G (IV.2) B + H + 1 == D with carry (VI.3) A + G == F (IV.3) A + D + 1 == E with carry, as no carry in (III.2) where a == b means a = b (modulo 10). This system is underdetermined. Solve the last 6 equation depending on D. G == 2D + 1 from (II.3) A == D + 1 with (III.2) H == -2D - 2 with (II.2) B == 3D + 1 with (IV.2) F == 3D + 2 with (VI.3) E == 2D + 2 with (IV.3) As E=B <=> D=1 we know that D >= 2. Otherwise the first digit of (I) gives A*D = (D+1)*D <= C < 10 so only D = 2 is possible. Therefore A=3, H=4, G=5, E=6, B=7, and F=8. The digits left for J and C are 1 and 9. 379 * 26 = 9854 + * - 1241 + 259 = 1500 ---------------------- 1620 + 6734 = 8354 References: Hoer Zu, No 38, 2001-09-14