9.10

Part of I Soros Olympiad 1994-95 (Rus + Ukr)

Problems(1)

multiple of n with digits only 8,9 (I Soros Olympiad 1994-95 R1 9.10 10.10 11.9)

Source:

For which natural

n

there exists a natural number multiple of

n

, whose decimal notation consists only of the digits

8

9

(possibly only from numbers

8

or only from numbers

9

number theorymultipleDigits