Is this a fun math fact?

I just came across this and felt compelled to share. You do not need to be a math geek to appreciate it, though it probably helps.

Take a prime number other than 2 or 5, 7 for example. Now look at one over the number, 1/7 in our case. As I hope you recall, this will be a repeating decimal. For prime numbers, the sequence will always be of the form .a1 a2…an a1a2…an…, and so on.

1/7 = .142857142857… If the number of digits in the repeating sequence is even, take the last half and add it to the first half, 142 + 857 = 999, and you will always get all nines.

This is known as Midy’s Theorem. For the mathematically inclined, this Wikipedia article has a nice description.