24.rb

def correct? input
  if 24 == input
    puts "great job! you did it!"
    true
  else
    puts "please try again"
    false
  end
end

while true
  begin
    user_input = gets
    int = Integer user_input
    break if correct? int
  rescue ArgumentError => e
    puts "invalid characters entered"
    puts "please try again"
    puts
  end
end