Call an integer a two-three integer if it is greater than 1 and has the form

2^a 3^b, wherea >= 0 andb >= 0. Express 19992000 as a sum of two-three integers so that none of the summands divides another.Source: Eighth Korean Mathematical Olympiad (Crux Math. Dec 1999)© Copyright 2000 Stan Wagon. Reproduced with permission.

9 February 2000