So for the funzies of it, and to bring a little more light-hearted-ness into OT, I have decided to, once a day, post a totally random and mostly useless math fact in this thread.

So, without further ado...

**FACT #1:**

Do you know how to check if a larger number is divisible by 7 with using a calculator?

One way is take the last digit in the number, double it, and minus it from the beginning numbers. If the number you're left with is divisible by 7 so was the original number.

E.g. 1855.

185 - (5 x 2)= 175.

17 - (5 x 2) = 7.

Thus 1855 is divisible by 7.

There is another test as well a tad more complicated. In this one you times each digit by a number and sum them together. Starting from the right-hand side you times each digit by **1, 3, 2, 6, 4, 5** and repeat again if there are more digits. If this sum is divisible by 7 so is the number.

E.g. __1855__

(__5__ x **1**) + (__5__ x **3**) + (__8__ x **2**) + (__1__ x **6**)

= 5 + 15 + 16 + 6 = 42 which is divisible by 7.

BONUS FACT: Did you know a square is a special type of rectangle and a circle is a special type of ellipse.

**FACT #2: **

Many of you may have heard of the Fibonacci Squence which is found by adding the 2 pervious numbers in the seqeunce;0, 1, 1, 2, 3, 5, 8, 13 ....

But did you know to find the nth term all you need to do is put it into his formala,without knowing the two pervious numbers...

an = (1/sqrt(5))*(((1 + sqrt(5))/2)^n + ((1 - sqrt(5)/2)^n)

Where a0 = 0 and a1 = 1.

Try it for yourself!

FACT #3: Inequalities don't exist for complex numbers

**BONUS FACT:** You can't square an inequality, unless you know both sides are of the same sign.

**FACT #4**: Four is the only number in the English language that is spelled with the same amount of letters as it represents.

**BONUS FACT:** Forty is the only number that has all its letters in alphabetical order.

**FACT #5:** 169,518,829,100,544,000,000,000,000,000 ways to play the first ten moves in a game of chess!

**FACT #6: **

1 x 1 = 1

11 x 11 = 121

111 x 111 = 12321

1111 x 1111 = 1234321

11111 x 11111 = 123454321

111111 x 111111 = 12345654321

1111111 x 1111111 = 1234567654321

11111111 x 11111111 = 123456787654321

111111111 x 111111111 = 12345678987654321

**BONUS FACT: **

1 x 9 + 2 = 11

12 x 9 + 3 = 111

123 x 9 + 4 = 1111

1234 x 9 + 5 = 11111

12345 x 9 + 6 = 111111

123456 x 9 + 7 = 1111111

1234567 x 9 + 8 = 11111111

12345678 x 9 + 9 = 111111111

123456789 x 9 + 10 = 111111111

**FACT #7**

2519 Mod 2 = 1

2519 Mod 3 = 2

2519 Mod 4 = 3

2519 Mod 5 = 4

2519 Mod 6 = 5

2519 Mod 7 = 6

2519 Mod 8 = 7

2519 Mod 9 = 8

2519 Mod 10 = 9

**FACT #8**

Did you know 1 x 10^69 is a duovigintillion.