Image: Melchoir

.99999 repeating is the representation of an endless string of 9s. Just when you think it should end, add another 9. Then do it again. Intuition tells us that without rounding this number is less than 1. We know it must end in a 9, and any decimal that starts 0.999… regardless of how many 9s you write, has to be less than 1. Well here is proof that you are wrong!

x = .999…
10x = 9.999…
10x – x = 9.999… – .999…
9x = 9
x = 1

How is this even possible? Why wouldn’t you just right 1 instead of .9 repeating? Now you can – if anyone questions you show this proof to blow their mind! You also now have the right to tell the joke “How many mathematicians does it take to change a lightbulb? Point nine repeating!”