The proof, known to be so hard that a mathematician once offered 10 martinis to whoever could figure it out, uses number ...

Examining mistakes gives students a chance to discuss misconceptions openly and find new approaches to solving problems.

In Guinness World Records, you'll find the shortest, tallest and fastest. Behind the spectacle is an auditing system so strict it has crushed many more record attempts than it has certified.

A deduction cuts the income you're taxed on, which can mean a lower bill. A credit cuts your tax bill directly. Learn more about common tax breaks and write-offs — and how to claim them. Many, or all, ...

Wholesale price/trade-in value. This is essentially a car's trade-in value to a dealer, who will likely sell it to someone ...