Two Digit Numbers
Math brain teasers require computations to solve.
Take the 2digit number 45.
Square it (45 x 45) to make 2025
Split this 4digit 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 2digit number which does the same?
Comments
Piffle
Jul 09, 2002
 This is a good one, I think. Good job. 
peppermintwist
Jul 09, 2002
 Clever! 
george1978
Jul 12, 2002
 i liked this one 
rufio
Aug 21, 2002
 "Can you find another 2digit number which does the same?" The correct answer, in my case, was "No." TECHNICALLY, it was the right answer. 
Smithy
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. 
lessthanjake789
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! 
Jimbo
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. 
c0forerunner0
Feb 18, 2013
 How about 10?
Take the 2digit 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. 
spikethru4
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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