Brain teaser: Can you crack the code and find the missing number in the triangle? A popular online math puzzle involves finding a missing number in triangles by using a simple addition rule ...

Alongside the mind-boggling brain teaser, he wrote, “Can you still crack the code?” The brain teaser features a lock that can only be opened with a four-digit code.

By carefully observing and analyzing the pattern of activity in the brain, researchers have found that they can tell what number a person has just seen. They can similarly tell how many dots a ...

Imagine a number lock with a three-digit code, and you're given five clues to crack it open. First, one digit is in the correct spot. Second, one digit is right, but it's in the wrong place.

Can they crack your code if they “intercept” your message? Extra: What if the person who intercepts your message knows about Caesar ciphers? Does that make it easier to crack the code?