Is there a way to tell if 12! / (7!5!) is an integer without fully working it out?
In my calculations, I've only managed to simplify it to:
12 x 11 x 10 x 9 x 8 / 5 x 4 x 3 x 2 x 1
..which would still take around 40 precious seconds to work out if it equals an integer..is there a shortcut?
In my calculations, I've only managed to simplify it to:
12 x 11 x 10 x 9 x 8 / 5 x 4 x 3 x 2 x 1
..which would still take around 40 precious seconds to work out if it equals an integer..is there a shortcut?
