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Two Digit Numbers

Math brain teasers require computations to solve.


Puzzle ID:#5101
Fun:*** (2.2)
Difficulty:*** (2.22)
Submitted By:mad-adeAhu***
Corrected By:boodler




Take the 2-digit number 45.
Square it (45 x 45) to make 2025
Split this 4-digit number in half to make 20 and 25
Add them (20 + 25) to make 45
Which is what you started with.
Can you find another 2-digit number which does the same?

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Jul 09, 2002

This is a good one, I think. Good job.
Jul 09, 2002

Jul 12, 2002

i liked this one
Aug 21, 2002

"Can you find another 2-digit number which does the same?" The correct answer, in my case, was "No." TECHNICALLY, it was the right answer.
Aug 20, 2003

d'oh. Rufio - I was gonna say that. You beat me to it by about a year. Except I was gonna say yes.
Oct 14, 2006

no one has commented in just about forever on this teaser. clever and tough. id be surprised if you figured that out all on your own, unless you have a system for it. id be interested to hear it actually. if its just a fact then - now i know, and thanks!
May 11, 2009

It's easily done with a spreadsheet but if you try it algebraically, it is hard to deal with the bit where you split the number in half. This step has a fraction in it which can be removed in a spreadsheet by the 'Round Down' function but it is much more difficult to deal with the remainder in Algebra.
I believe that teasers like this belong in the 'Trivia' category unless you accept that creating a spreadsheet is a legitimate way to solve Mathematical teasers.
Feb 18, 2013

How about 10?

Take the 2-digit number 10.
Square it to make 100
Split this number to make 10 and 0
Add them to make 10
Which is what you started with.
Feb 18, 2013

Well, if you split 100 according to the rules, you'd end up with 01 and 00, which sums to 1, so no.

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