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  1. #1
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    Phone number witchcraft

    Not really a puzzle but still good fun:

    This will only work if you have a seven digit phone no. If you are in the UK and your number is like 0208 123 4567 just make it 123 4567.

    Now here is the witchcraft:

    Grab a calculator.
    Type in the first three numbers of your seven digit telephone number.
    Multiply by 80
    Add one
    Multiply by 250
    Add the last four digits of your number
    Add them again
    Subtract 250
    Divide by 2

    What is the final number?
    Jerry

  2. #2
    WS Lounge VIP sdckapr's Avatar
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    Re: Phone number witchcraft

    Start with x = 3 dig, y = last four
    Type in the first three numbers of your seven digit telephone number.
    Multiply by 80 [80x]
    Add one[80x +1]
    Multiply by 250 [20,000x +250]
    Add the last four digits of your number [20,000x + 250 +y]
    Add them again [20,000x + 250 +2y]
    Subtract 250[20,000x +2y]
    Divide by 2 [10,000x +y]

    10,000x moves the number (x) 4 places to the left (adds 4 zeroes) and then you add the last 4 digit number (y)

    Steve

  3. #3
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    Re: Phone number witchcraft

    Thanks for diagnosing it Steve.

    I have a penchant for these types of number games, I don't know if you saw some of my own in scuttlebutt at the end of last year (sadly the posts have expired now). This one is not my own as I saw it last night on a web page and thought I would share it.

    When I do these or create new ones I visualise them as two seperate entities( like you have by calling them x and y) and then put the calculations in two columns in a spreadsheet and then manipulate the numbers in steps. In my opinion this one was not very well "disguised" as the factors of 80 and 250 gave a very big clue. Still fun though.
    Jerry

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