I recently learnt that in the US eggs are sold in packs of 12. And I now I'm annoyed that here in Russia we have only packs of 10. 12 has so many divisors: 2, 3, 4, and 6! 10 has only 2 and 5. If I decide to eat 3 eggs per day I have to buy 3 packs of 10 to finish them evenly.