(I) ABCDE - FGEE = AHBDE : - - (II) DI * HDB = BKDB ----------------------- (III) CDE + FKCD = KDGD (IV) (V) (VI) Solution: (I.1) E = 0 (VI) A = 1 (VI.2) G = 9 (as there is a carry) (IV') DI * CD = ABCD (IV'.1) I * D = D (mod 5) (II.1) I * B = B (mod 5) As not both B and D can be 5 we can divide by B or D and get I = 1 (mod 5). As A=1 is used already we get I=6 Furthermore B and D are even. (II) D * H <= B The smallest two not used numbers are 2 and 3. Therefore 2*3 <= B but 6 is used. The only even number left is B=8. (VI.1) D = 2 (III.2) C = 7 (VI.3) K = 5 (V.3) H = 3 (III.4) F = 4 18720 - 4900 = 13820 : - - 26 * 328 = 8528 ----------------------- 720 + 4572 = 5292 References: - Johannes Lehmann; Kurzweil durch Mathe, Urania Verlag 1988, ISBN 3-332-00239-2 Mathematische Schülerbücherei MSB Nr. 77 Chap: Heiterer Stundenplan, p87, 181 Problem 10