All mainstream credit card numbers obey a mathematical trick designed to catch the most common typos. It’s called the Luhn algorithm, named after IBM researcher Hans Peter Luhn, who patented it in ...

How much does credit card debt really cost you? Most people don’t even want to think about it, let alone do the math themselves. But with the federal reserve’s free and simple credit card repayment ...

Years ago, one of my closest friends found himself staring down about $30,000 in credit card debt. He was juggling multiple cards, paying 20%+ interest, and was extremely overwhelmed. Then he ...