Mathematical competitions in Belgium are held separately in each entity: French (Olympiade Mathematique Belge = Belgian Mathematical Olympiad, OMB) and Flamish/Dutch (Flanders Mathematical Olympiad, FMO). The OMB is held in a few rounds, the last of which (final) is divided into three levels - mini, midi, maxi (we don’t know whether this division is with respect to age or type of school), with four problems for each. The FMO consists of three rounds, where the first two are sets of multiple choice questions, while the final consists of four problems.
Belgium at International Competitions
Belgium participates at the IMO since 1969. Apparently, three best contestants on the final contest in each entity qualify for the IMO team. The best success of Belgium at the IMO was the 31-st place in 1996.