Birthday Paradox - Probability of shared birthdays

Video by KNOW (KnowNow).

The birthday paradox is a famous problem in probability theory that seems counterintuitive at first. It states that in a group of just 23 people, there's a better than even chance (over 50%) that at least two people share the same birthday.
It's a surprising result because our intuition often tells us that we would need a much larger group for a shared birthday to be likely.