There are many opportunities to use 'four-digit PIN numbers' in our daily lives, such as credit card PIN numbers, smartphone passcodes, and PC unlock codes. In all cases, we should use four-digit ...

The iPhone calculator is great for crunching numbers in a pinch, but you can also use it to have some fun with your friends and family. Here are some cool calculator tricks you can use to find someone ...

Adding larger numbers in your head is not always easy. If you need to use pen and paper, then the column method is a good way to add. It involves writing one number beneath the other, so that the ...

There's no reason to believe a six-digit PIN is substantially more secure than a four-digit PIN, according to a research paper on mobile phone passcodes. The reason? When asked to choose longer PINs, ...

Choosing a phone PIN code that's easy to remember might be a time-saver. It's also a potential security risk. If your phone or another device is lost or stolen, an easily-guessed PIN code makes it ...

Subtracting larger numbers in your head is not always easy, so you can use the column method to take one number away from another. You write the larger number above the smaller number, so that the ...