Brain Teasers
2+2=5
Using only two 2's and any combination of mathematical signs, symbols and functions can you make 5?
Answer
SQRT(.2 ^ -2)Take .2 and raise it to the power of -2 and then take the square root.
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Comments
2+2+(2/2) is a much simpler way
ya i know... i just put the more complex one...
Guys, the teaser says to use only TWO 2's. Gizzer's answer is not valid.
he did use only 2's... or does him making the 2's into 1's not count... i know the one i put up there works...
No, Chemicalboy, the problem is in the number of 2's that Gizzer is using. His solution uses FOUR 2's. The teaser says that you can only use TWO 2's. The answer to the teaser is fine. Gizzer's answer uses too many 2's.
Oh hehehe... I even made this teaser up... how did i miss that.
well it asks if you can so I just said the answer was no
good answer!
Did you know you can make any number that is a power of 2 by using the square root and logarithm function with just 2 2's. 4 (for example) is the log of 2 to the base sqrt(sqrt(2)). 8 is the log of 2 to the base sqrt(sqrt(sqrt(2))) and so on. In fact if you extend this principle to 4 fours, you can make every possible number with just 4 fours - a universal solution!
SQRT((.2)^(-2))=5.
It says to use two 2's, that doesn't mean you have to use only two 2's.
2+5-2=5 that uses two 2's, equals five, and stears clear of the squares and square root theory.
2+5-2=5 that uses two 2's, equals five, and stears clear of the squares and square root theory.
Jul 05, 2003
going back to the point that u can only use 2 twos.. he didnt use a 2.. he used a 0.2 .. which is not 2. In the case where u can use any combination of two's.. an answer could also be: (22 / 2)+ (-2) + (-2) + (-2) = 5
lol.. thats weird.. but its what i thought of first...
good teaser though... keep it up
lol.. thats weird.. but its what i thought of first...
good teaser though... keep it up
You said what?
.... .2 is a type of 2....
I mean, are you all math professors or something?What the heck is a power?
2 raised to the second power is just 2 squared....
You should have said that earlier
well i am assuming that people that are registered are over 13...
What is Chemicalboy on about... ...
Basically, he's saying he thought a power was common knowledge. Also, using two 2's, meant using the 2 digit, not the unit.
exactly... thanks tissue for clearing that up
I waited 5 minutes for new comments on this
or (2+2+2+2+2)/2
How about 2 to the power of 2, plus two to the power of 0. That would be 4 + 1 = 5!!!
I said only use 2 twos
Hey guys I am gonna say it one last time... Only two 2's!!!
SQR(2)+TRUNC(SQRT(2))
SQR - Square
SQRT - Square root
TRUNC - Truncatenate or Round to the nearest lower integer
SQR - Square
SQRT - Square root
TRUNC - Truncatenate or Round to the nearest lower integer
How about the summation of 2 plus 2?
Another answer, assuming programming code is allowed, is (2++) + 2.
In C++, adding ++ to a number means "The number + 1".
In C++, adding ++ to a number means "The number + 1".
whoa thats so like mathey
i said i said the quantity of (2 over 2+2) times 2 plus 2 plus 2 but that uses way more than two 2s so that doesnt ork for this teaser
i said i said the quantity of (2 over 2+2) times 2 plus 2 plus 2 but that uses way more than two 2s so that doesnt ork for this teaser
the anser of cccc's question is:
a power is: multiplying a number by itself a set number of times, like this: 4 to the 3rd power is 4x4x4 is 64. and 3 to the 2nd power is 3x3 is 9. and by the way, 3x3 is 3 squared. and, 3x3x3 is 3 cubed. get it?
a power is: multiplying a number by itself a set number of times, like this: 4 to the 3rd power is 4x4x4 is 64. and 3 to the 2nd power is 3x3 is 9. and by the way, 3x3 is 3 squared. and, 3x3x3 is 3 cubed. get it?
In about 10 seconds I came up with CEIL[SQRT((2+2)!)] where CEIL[x] is effectively rounding up the answer to the next highest integer in this case.
So CEIL[SQRT((2+2)!)] = CEIL[SQRT(4!)] = CEIL[SQRT(24)] = CEIL[~4.9] = 5
Seemed pretty easy and I didn't need to change the 2 into .2. (2+2 can also be 2x2 or 2^2)
So CEIL[SQRT((2+2)!)] = CEIL[SQRT(4!)] = CEIL[SQRT(24)] = CEIL[~4.9] = 5
Seemed pretty easy and I didn't need to change the 2 into .2. (2+2 can also be 2x2 or 2^2)
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