(I) ABBC : DDE = DF + + * (II) AGFG - AHIB = KKG ---------------------- (III) KGEH + ACKE = FCII (IV) (V) (VI) Solution: (V.1) B = 0 (III*) K + A <= F (II.2) K + I = F as K < F (II.3) K + H = G (IV.2) F + 1 = E (IV.1) C + G = H + 10 (II.3)+(IV.1) K + C = 10 (IV.4) 2 A = K (III*)+(IV.4)+(IV.2) 3A+1 <= E <= 9 => A <= 2 (I) D * D <= A <= 2 => D = 1 and A = 2 (V.2) I + 1 = K (V.3) H + 1 = C (IV.1)+(V.3) G = 9 Then we get the remaining variables K = 2A = 4, I = 2A-1 = 3, F = 4A-1 = 7, E = 4A, C = 10-2A = 6, H = 9-2A = 5. 2006 : 118 = 17 + + * 2979 - 2530 = 449 ---------------------- 4985 + 2648 = 7633 References: Hoer Zu, No 29, 2003-07-11