Everything is returned correctly.
puts 8/3.ceil == 2
#=> true, because 8/3 returns an Integer, 2
puts 8/3.floor == 2
#=> true, because 8/3 returns an Integer, 2
puts 2.67.ceil == 2
#=> false, because 2.67.ceil is 3
puts 2.67.floor == 2
#=> true, because 2.67.floor is 2
To make things of more sense here, you can convert results to Float:
(8.to_f / 3).ceil == 2 #=> false
(8.to_f / 3).floor == 2 #=> true
2.67.ceil == 2 #=> false
2.67.floor == 2 #=> true
Another thing to bear in mind, that having written 8/3.ceil is actually 8 / (3.ceil), because the . binds stronger than /. (thx @tadman)
Yet another thing to mention, is that (thx @Stefan):
There’s also
fdivto perform floating point division, i.e.
8.fdiv(3).ceil. And Ruby also comes with a niceRationalclass:(8/3r).ceil.