On cloud nine. A pretty penny. The sixty-four-thousand-dollar question. Have you heard these crazy expressions? People use them even when the sky is cloud-free and there are no pennies in sight! That's because these sayings are idioms—phrases that mean something different than what the words in them actually say. But don't let idioms put you at sixes and sevens. Let's explore a variety of idioms related to money and numbers and figure out what people really mean when they use them.