# We don't normally do this

because otherwise we could just fill the Blog with emails but look - we just tried this...or rather Jasper and Jeremy, our editor and deputy for the day just tried it, and it does work. We don't care how, we just marvel at it.

It was sent in by Andrew Willis. Thank you.

"YOUR AGE BY EATING OUT

Don't tell me your age; you probably would tell a falsehood anyway-but your waiter may know!

YOUR AGE BY DINER & RESTAURANT MATH

This is pretty neat

DON'T CHEAT BY SCROLLING DOWN FIRST!

It takes less than a minute .

Work this out as you read ...

Be sure you don't read the bottom until you've worked it out!

This is not one of those waste of time things, it's fun.

N.B. you may need a pen & paper for two or three calculations.

1. First of all, pick the number of times a week that you would like to go out to eat. (more than once but less than 10)

2. Multiply this number by 2 (just to be bold)

3. Add 5

4. Multiply it by 50

5. If you have already had your birthday this year add 1757 .....

If you haven't, add 1756.

6. Now subtract the four digit year that you were born.

You should have a three digit number

The first digit of this was your original number

(I.e., how! Many times you want to go out to restaurants in a week)

The next two numbers are

YOUR AGE! (Oh YES, it is!!!!!)

THIS IS THE ONLY YEAR (2007) IT WILL EVER WORK, SO SPREAD IT AROUND WHILE IT LASTS"

Big Sisterwrote:Oh, Eddie, I just LOVE these maths games. Yes, indeed, it does work.

There's another one I know. But I won't email it to you. Promise!

witchiwomanwrote:Cool - I'm sure theres a very simple explanation but frankly I don't care and don't want to know! :)

Fionawrote:Wow, it does work! How??

Val Pwrote:Good grief - it works!

Come on then you mathematical spoilsports out there, put down your six-sigma presentations and tell us how it works then?

Lee Vitoutwrote:According to my calculations I'm 96! I'll try again.

Electric Dragonwrote:Why does this work? Well, anyone with a GCSE in Maths could tell you. Essentially what it's telling you is that your age is 2007 (or 6 if you've not yet had your birthday) minus your birth year. The rest of the maths is simply misdirection to exploit the way people get frightened or mystified by anything vaguely mathematical. It is true that THIS IS THE ONLY YEAR IT WILL EVER WORK - because next year, you have to replace 1756 and 1757 with 1757 and 1758 respectively.

It reminds me of a verse from Lewis Carroll's Hunting of the Snark:

"Taking Three as the subject to reason about—

A convenient number to state—

We add Seven, and Ten, and then multiply out

By One Thousand diminished by Eight.

"The result we proceed to divide, as you see,

By Nine Hundred and Ninety and Two:

Then subtract Seventeen, and the answer must be

Exactly and perfectly true."

jonniewrote:Wow -- Don't spoil it electric dragon :-(

It's magic okay!

John H.wrote:Electric Dragon is rather more eloquent than me, but spot on. The "add 2 and multiply by 50" steps gives you a figure of as many hundreds as the number of times you said you wanted to eat out (i.e. 3 times = 300, 2 time = 200, etc) which then gives you the same number back at the end, and the "plus 5 and multiply by 50" give you the 250 you need to make up the difference between 2007 and 1757/6.

If you're over a hundred, it doesn't work.

Abi Bradywrote:note the hidden encoding of 2007 in the steps. multiply by 2, add 5, multiply by 50, then add 1757. or, in other words, multiply by 100, and add 2007!

Timwrote:Okay, so it works.

But I must ask why I just wasted 3 minutes of my time reading and doing it?

Hardly a revelation!

Fearless Fredwrote:Well, it was more fun that the TWO six sigma presentations I've just done!

Val Pwrote:Two, was it Ffred? Hope they were dazzled by your brilliance, and realised whose company you had to sacrifice last night to get them polished!

Wonkowrote:There's another neat arithmatic trick you can do, which you can present as mind reading:

Think of a number between 1 and 10.

Multiply that number by 9

If you have a two digit answer, add the two numbers together. E.g. if you have 45 as your answer, add 4 and 5.

Now subtract 5 from your total.

If you were to think of the alphabet being numbered, so a=1, b=2 through to z=26, take the number you now have and equate it to a letter of the alphabet.

Now think of a country that begins with that letter.

Then think of an animal that begins with the second letter of that country's name.

Finally, think of the colour of that animal.

There is a very good chance that you've just thought of a grey elephant from Denmark.

The number you should have ended up with was four, and the letter was therefore D

Stewart Mwrote:Don't care that its just a simple maths trick. its great fun! Of course I know how old I am so did not need to work it out

RJDwrote:Fearless - You should have done a twelve sigma presentation and got it over with!

Humphwrote:I could have told you that even though I do not have a GCSE in maths, E Dragon (6). I have a GCE O-Level! Well it was a thread about our age, wasn't it?

H.

Otto's Mummywrote:Wow - as I have a serious (and I mean serious) maths hangup, I struggled at point 2!!! But after finding the calculator I was spooked! Trouble is, I thought it would tell me the real number of times I'd like to eat out (once a month around here) and not the little fib I had to put in.

John H.wrote:Wonko, obviously heard that before. But it's only today that I've realised the that the "multiply by 9" step is always going to result in a number where adding the digits equals nine. Why's that then? And what numbers act in a similar way?

Anyway, my black umbrella from Dubai was clearly wrong.

Chris Ghotiwrote:I thought the rule was meant to be that all arithmetical puzzles always came out with the answer 23, or some number that can be juggled to reach 23.

Hail Eris! All Hail Discordia!

(Well, it was all about our age, wasn't it?)

Wonkowrote:John H: You're quite correct, the multiply by nine part is the sneaky bit. It assures that you always get nine as the next part, so subtracting five will always give four, and so the letter will always be D. The only other option I have heard is a black and white ostrich from the Dominican Republic, so congratulations on being creative!

;o) []

Little Redwrote:John H at 18. Probably because Dubai is a city not a country...

There aren't may D's. But we managed to get eel instead of elephant. But it was still grey and fom Denmark. So that's still spooky.

witchiwomanwrote:Along the lines of 'wouldn't normally do this' but this was so bizarre....and a little stomach churning

http://news.bbc.co.uk/1/hi/world/americas/4313978.stm

John H.wrote:Thanks Little Red - it's always good to be put right when you're spouting rubbish.

How about Djibouti? And a big eye tunny? Ooo, they're grey too. Spooky!

Ed Iglehartwrote:WW,

Only for the snake.

xx

ed

DI Wymanwrote:....nice one......seems that I am the same age as Gillian...:)

Gillianwrote:DIWy (25) Actually, I think you'll find I'm younger than you! ;o)

Sodom&Gomorrahwrote:Wonko,

sorry to disappoint. Black Jackdaw from Djibuti(?).

Loved the test though, and yes the digits of all multiples of 9 below 10 add up to 9.

Val Pwrote:...and 11 months younger than I am!

madmarywrote:I don't care how it works, like jonnie said it's magical! I'm not telling anyone how many times I'd like to eat out though!

Mary

mittfhwrote:Anyone tried meddling with SQRT(-1) yet? The one aspect of A level Maths I could never get my head around was complex numbers. I'm sure they have their uses, but basing calculations on numbers that even mathematicians call "Imaginary" completely threw me.

As for number games, my favourite involves no calculations at all - just logic. Take a 9x9 square, and fill it in so that each row, column and 3x3 block contains the digits 1 to 9.

Big Sisterwrote:mittfh: Hm. Another Sudoku fan/addict, I see.

Mind you, the last couple of weeks I've been struggling a bit with the fiendish. Could my brain be finally frying [too much frogging, I hear you say ....]

Wonkowrote:S&G: Well, that's a new one! 12/10 for creativity! Well done. ;o) []