puts 1.1.ceil # => 2: ceiling: smallest integer >= its argument
puts -1.1.ceil # => -1: ceiling: smallest integer >= its argument
puts 1.9.floor # => 1: floor: largest integer <= its argument
puts -1.9.floor # => -2: floor: largest integer <= its argument
puts 1.1.round # => 1: round to nearest integer
puts 0.5.round # => 1: round toward infinity when halfway between integers
puts -0.5.round # => -1: or round toward negative infinity
puts 1.1.truncate # => 1: chop off fractional part: round toward zero
puts -1.1.to_i # => -1: synonym for truncate