# Maths trick

Graham. 17:37 25 Apr 08
Locked

1. Grab a calculator. (You won't be able to do this one in your head)
2. Key in the first three digits of your home phone number (NOT the area code)
3 Multiply by 8
5. Multiply by 250
8. Subtract 250
9. Divide number by 2

Bingalau 17:57 25 Apr 08

No?

VoG II 18:00 25 Apr 08

Nope.

Graham. 18:05 25 Apr 08

Must admit, I didn't try it myself. I get these passed on by email. Oh well, forget it.

shellship 18:06 25 Apr 08

Yup - it's my phone number. Obvious really but I thought VoG, being the mathmatical genius he is, would have worked that one out in nanoseconds!
Sorry VoG - must learn how to include TM when on Forum.

GANDALF <|:-)> 18:07 25 Apr 08

Rather amazingly it worked with my phone number.

G

TopCat® 18:41 25 Apr 08

I have only a five digit number so I added a zero for steps 7 and 8. Still came up with my phone number though, plus that zero. TC.

Woolwell 18:43 25 Apr 08

Not a trick.
Using algebra:
Where A = first three digits, B - last three numbers

Using the procedure above you get:
(250(8A + 1) + 2B - 250)/2
which becomes
(2000A + 250 + 2B - 250)/2
which results in 1000A + B

eg telephone number 123456 A=123 B=456
1000A = 123000 + 456 = 123456

Hope that this is clear.

Monoux 18:44 25 Apr 08

Quickbeam 18:46 25 Apr 08

No, but it's enough to know there in an infallible formula:)

Graham. 18:47 25 Apr 08

So it only works with 6 digit numbers?

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