Numbers are really the bread and butter of memory competitions. Apart from the two written and one spoken numbers disciplines in every competition, many people still think of binary and cards as being just numbers presented a slightly different way.
I've personally never found numbers as much fun as cards, I don't know why. Maybe it's the tactile pleasure of shuffling them in your hands? Or maybe decimal numbers are just intrinsically a bit more boring than binary digits?
Anyway, the scores in numbers seem to be escalating at a rate of knots lately - it's not so long ago that 2000 in an hour was still a distant target, but now the top memorisers have left that mark in the dust. And five-minute numbers is rocketing forward even more quickly, with scores of 500 now being recorded. Fifteen-minute numbers, because it's only done at National Standard competitions, is maybe lagging behind a bit, but the days when I held the record for years with just over eight hundred are long gone now...
Numbers have always been a part of the memory championship scene, of course, and the distinctive rule that they come in rows of 40 has been around for as long as anyone can remember - but why 40? It puts people who memorise the numbers in groups of three at a bit of a disadvantage, because that puts 13-and-a-third images on each row. Obviously, when memory competitions started, everyone had a two-digit system, but things have moved on since then. Maybe we should consider changing the rules and giving the numbers in rows of 36? That would accommodate everybody's systems!