An American in Provence

Ever since I can remember, I have been fascinated by numbers, especially their relations with each other.
For example, riding up the ski lift I would watch the chairs going by, and noticing the number of each one, try to find the highest number, or find the chair with the number of my birthdate, or count how many there were, or whatever.

Riding in the car during interminable car trips, I would watch the mile markers on the highway go by. I would often remember exactly how many miles we had to go in Kansas, or count how many minutes before passing each mile marker.

Driving home from work, I have divided up the last 5 km of my route (the slowest part) into nine different sections, and then I count how many minutes it takes me to get through each section, and then sing to myself
2-1-2-3-1-1-1-1-4 (or however minutes each section took).

Trying to take a nap the other day, my mind was whirring away, with different numbers in my head.
45. Now if I flip that, that is 54. Nine numbers apart.
Hmm.
Let's see. If I take 24, then it is 18 apart from 42. Huh. a multiple of nine.
Let's see, then if I take the second number 4, and then subtract the first number 2, then multiply that by nine and then add that to the first number (24) I get 42. Interesting. So the difference between the two numbers is the multiple by which 9 must be multiplied, then the sum added to the first number to get its reverse.
Now wait a minute, what if it is a number with the second number less than the first, like 51? Let's see, 1-5=-4. -4 times 9 = -36, which when added to 51 equals 15. Cool!
Okay, time to go to sleep.

I'm sure I'm not the first person to figure this out, but it is just to give you an idea of the strange things that wander through my mind. I was anxious to get home and verify my theory, so I wrote up an Excel spreadsheet. It works. Try it. Amaze your friends with your amazing math skills.
Just be sure you can add for example 36 and 27 in your head.
It even tecnically works for numbers such as the following:
9: 09 + (9-0)*9 = 9 + 81 = 90
44: 44 + (4-4)*9= 44 + 0 = 44

Now, this being said, the French number system really gets on my nerves. I mean honestly, who came up with the names for their numbers (70-99)?!
99 = four twenties, a ten, and a nine
what a mouthful.
Here is my new French numbering system:
40= quarante
50= cinquante
60= soixante
70= septante
80= huitante
90= neuffante
99= neuffante-neuf.
So much better!