IMO Shortlist 1962 problem 1
Dodao/la: arhiva2. travnja 2012.
Find the smallest natural number
which has the following properties:
a) Its decimal representation has a 6 as the last digit.
b) If the last digit 6 is erased and placed in front of the remaining digits, the resulting number is four times as large as the original number
Izvor: Međunarodna matematička olimpijada, shortlist 1962