Make a 5 !
Can you take two 2's and make a 5 *
* using any mathematical operation(s)
* using any mathematical operation(s)
Labels: mathemagic, trickofmind
posted by Rajesh Lal at
9:22 AM
Wednesday, November 7, 2007
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46 Comments:
a mathematical equation with a sense of imagination. 2+2=5. duh.lol
225... take the two 2's, and you're left with five.
2^1+2^2=5
sorry... 2^0+2^2=5... the first way I did it, equaled 6.
will you are using three 2's the question says two 2's
I made 2+2=5....
2 to the Zero power is 1
and 2 squared (second power) is 4
1+4=5
if you flip the 2 upside down, you get a 5.
if you have two 2's and flip'em, you get two 5's!
take a 5 away, and yes, i can make two 2's a 5!
:)
2 power 0 + 2 power 2 [1+4=5]
2+2+1=5
the question said to use two 2s, but didn't say anything about not adding other numbers also.
Dillon
p.s. i'm 13 years old
dillon you are too young to know everything :)
Here is an evil answer: 2x+2y=5, solve for x and y :D
2 + 2 = 4 ..add a 1 and you get 5 :P
2^2 + 2^(2-2) = 5
how man y2's it said only two
Take sqrt(22) and round up to the nearest whole number and you get 5.
Cube Root (2) + (2)Squared = 5 (1 Decimal Place)
(2+2+2+2+2)/2
I can't make the symbol... but it would be a Sigma, on the top a 2 and then = i^2
25-45+9/4=16-36+9/4
(5-3/2)^2=(4-3/2)^2
Square(5-3/2)^2=Square(4-3/2)^2
5-3/2=4-3/2
5=4
5=2*2
yea 2+2+2+2+2/2
can you TAKE two 2's and make a 5
9 - 2 - 2 = 5
yay =]
2*2+(2/2)or
(2*2+2)/2+2
Easy=) 5/2 + 5/2=5
5/2 is equivalent to 2.5
2+2+2+2+2=10/2=5
use a roof function ie. [x] rounds up to the nearest integer.
[sqrt of 22]= 5 because it rounds up to 5
it takes what soyelkabron says and makes it a mathematical function
I liked the Ceiling(sqrt(22)) answer... but I'm looking for a response from the puzzle creator here for as to whether this is in fact, the valid one... and if so, it's not a very good puzzle, since sqrt(22) is really just 22^(1/2), which is using 3 2's... (and shame on the rest of you for not accounting for this in your solutions...) -- but, I'm stumped here, and quite curious to see how this 'mathemagic' is working...
start with a nine
9-2-2=5
Can the author post the official answer?
I would rotate the 2's 180 degrees, then place one 2 on top of the other to make a 5.
I liked Will's evil algebra answer:
2x+2y=5
But I think I have a much simpler one:
2+2≠5
I don't care if it doesn't count.
2!+2=5 (2+1)+2=5
Thanks for noticing that sqrt(22) is actually 22^(1/2). I actually noticed it after I posted it. And for the anonymous above: 2! is not 2+1, but 2*1
Umm 2! = 2 (2*1), not (2+1)
so,
2!+2≠5 (2*1)+2=4
ANSWER
------------------------
(sqrt((.2) ^ (-2)) = 5
and also
Ceil(sqrt(22)) = 5
Nobody got the FIRST ANSWER
Second ANSWER GOT RIGHT
------------------------
soyelkabron
Take sqrt(22) and round up to the nearest whole number and you get 5.
and
Anonymous guy
use a roof function ie. [x] rounds up to the nearest integer.
[sqrt of 22]= 5 because it rounds up to 5
------------------------
ANOTHER INTERESTING ANSWER
-------------------
related to programming
2 + 2++ = 5;
in some compilers ++ operator adds 1 :)
HA :D
Actually, I like the programming answer... albeit QUITE non-obvious... and a little dubious as well... but I must say I really don't like the SQRT() answer... since that's inherently using another 2... it's just ()^(1/2)... but keep 'em coming Rajesh -- just d/l'd the gadget a few days ago and loving it :D
thanks for your comment charles , made my day
if the sqrt function is allowed then 2^2 + 2^0 must be accepted as an answer
sqrt is a mathematical operation
and it is still using only two 2's
where as your is three 2's and one 0 also
sqrt is not a mathematical "operator", its a "function"...the operator being used in these answers is the EXPONENTIATION operator
5-2=3+2=5
5-2=3+2=5
2*2+2/2=5
fIVe
^^
4
I don't like the original answer since it uses 0.2 (including a zero) and sqrt (which is a power by 0.5).
Therefore I came up with a new answer, using binary logic:
two twos (MBL):
1010
using unary not:
!(1010)=0101 =(DEC) 5
assume a+b = c
then
1. 4a+4b=4c
2.5a+5b=5c
then
4(a+b-c)=5(a+b-c)
4=5
2+2 = 5 since LHS= RHS :o)
Although the last solution looks so elegant keep in mind you can't divide with zero, though I got you thinking :o)
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