'Tis always fun to break your friends' brains.

Most of you probably already know this, but I just want to remind you:

1/3 x 3 = 9/9 = 1

1/3 = .33 (repeating infinitely)

.33 x 3 = .99 (repeating infinitely)

.99 infinitely repeating is exactly the same as 1; no adding or rounding to it.

If you're just learning this and this is breaking your mind, just think about it:

What can you add to .99 repeating infinitely to make it 1?

The answer is absolutely nothing. Your first thought may be: .00 infinitely repeating with a 1 at the end. Think about that for a second. If you didn't already catch it, infinitely repeating decimals don't have an end. Plus, why would 0's go on and on like that? The simple yet complex fact is that .99 repeating infinitely and 1 are the exact same thing, but you get each by different methods, as you can see above.

Tell this to your friends and acquaintances, and marvel as their mind undergoes a stack overflow, and then they call you a nerd.