You'll find your credit card number either on the front or on the back of the card. Credit cards usually have 15 or 16 ...

A prime number is a number that is only divisible by one and itself, which is essentially saying that it has no divisor. That takes half of all possible numbers off the table right away (the evens), ...

If you've got the time, we've got the riddle. And it's time for a riddle about time: How many numbers are on a clock? It begins with the simplest of questions that, nevertheless, has no simple ...

When you move beyond trillions, there are some extremely mind-bending numbers, says Richard Fisher. Some of them are too large to fit in the mind – or even within the known Universe. What's the ...

Here’s a game: Ask a friend to give you any number and you’ll return one that’s bigger. Just add “1” to whatever number they come up with and you’re sure to win. The reason is that numbers go on ...

In the early 1970s mathematician Donald Knuth spent a sabbatical with his wife in Norway. The time was meant to be spent relaxing. Yet one night he woke up his partner in a state of agitation. He ...

Imaginary numbers might seem like unicorns and goblins — interesting but irrelevant to reality. But for describing matter at its roots, imaginary numbers turn out to be essential. They seem to be ...