Cash Register 1

cash_register_1.rb

#input amount due
puts "What is the amount due?"
due = gets.chomp.to_f
#input amount tendered
puts "What is the amount tendered?"
tendered = gets.chomp.to_f
#if tendered >= due, print receipt
change = (tendered-due).abs
change = '%.2f' % change
if tendered >= due
  puts "===Thank You!==="
  puts "The total change due is $#{change}"
  puts
  puts Time.now
  puts"================"

else
  #otherwise calculate shortfall, warn and exit
  puts "WARNING: Customer still owes $#{change}! Exiting..."
end

Edited to refine float decimal points and condense "shortfall" and "change" to "change" using absolute value.