OT-Math Puzzle

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[250(80x + 1) + 2y] - 250 _________________________ = 1000x + y 2

Basically, x is the first 3 digits of the phone number (or any value), and y is the last 4 digits of the phone number (or any value). Try it with single digit numbers and 2 digit numbers. Quilters are always saying how we need geometry, but algebra is our friend, too.

--Lia

It doesn't quite work with the UK phone numbers; but, if you use the last digit of the area code, it is definitely recognisable. Our phone numbers are 5+6, typically - except for London and some other unusual places. Cute 'trick'. I wonder what research student spent his 'homework' time working that one out? >g< . In message , ME-Judy writes

A lot of northern cities have 7 digit phone numbers, Manchester, Leeds, Sheffield, etc, wouldn't surprise me if the population in such cities is big enough to mean more people have a 7 digit phone number. The crucial bit of the trick is that the phone number is split between the last 4 digits and whatever is in front of it regardless of how long it is, so the puzzle could be rephrased to work for any phone number.

Cheers Anne

Cool....

Very cool. spooky.

amy in CNY

I was hoping someone here was a math-wizard! Thanks, Julia! I figured out what made it come out to the proper answer, but I LOVE the equation! ME-Judy

The trick is in believing, in your heart of hearts, that if it works for one set of numbers, then it must work always and forever. Algebra is not for those who belive in magic. If it works, then there's a reason it works. Once you've got it that there must be an equation out there, then you just fill in the blanks.

--Lia