OT Can you figure out this Bizarro game?

Oh this is going to drive me nuts. Please someone figure how it's done.

Try this. It's really funny. I got this in an email this morning. Who thinks these crazy things up.

While sitting at your desk, lift your right foot off the floor and make clockwise circles.

Now, while doing this, draw the number "6" in the air with your right hand.

Your foot will change direction.

Have a Great Day Everyone. Bettina _

I got part of it figgered out. For any combiation of four digits, the digits of the difference will add up to 9 or 18. So if the three digits you enter add up to less than 9, the program finds the number that brings total to 9. If your three add up to 9 or greater, then the response is the value that brings it to 18.

Now, it's gonna take a more mathematically enlightened person than me to explain why the digits of the differences add up to 9 or 18. I can deal with basic algebra OK, but combinatorics and permutations whizz over my head most days.

Val

You're right - they add up to 9 or 18 (Don't know how you found that!) But then, the check digit, how does the program always get that right, when it varies each time? See what I mean?

cancel that. I copy

*nod* It's just part of the way numbers work. They are absolutely beautiful if you look at the closely enough.

Here's a tip for you -- if you can't get a column of numbers to balance with the total you think you are supposed to get -- if the difference between the two is a factor of 9, it's probably a transpotition error. you've probably just written a number backwards or put it in the calculator backwards. handy for balancing your checkbook. Old bookkeepers secret!

Jewitch

Sheesh you guys. Well then, I feel stupider (see what I mean?) every day. I have never heard of the rule of 9s, and bookkeeping/billing/data software is a large part of my list of "done thats" over the years!

It's from older days of bookkeeping. Before computers.

Tina

Aaaaaagh!