Number Operation
There are four numbers: 5, 5, 5, and 1. The operations are missing, but the answer is known. You can use addition, subtraction, multiplication, and division to make the following equation true.
5 O 5 O 5 O 1 = 24.
Fill in the Os with either +, -, ◊, or \.
- Kevin Zhu
5 O 5 O 5 O 1 = 24.
Fill in the Os with either +, -, ◊, or \.
- Kevin Zhu
Labels: SharedPuzzle
posted by Rajesh Lal at
11:45 PM
29 Comments:
can u use barckets?
I smell the aroma of homework in this question!
alberto ayala says:
5*0+5+0*5+0-1=24
There would be 64 unique ways of placing +,=,*,/ in the equation, but I did not find one that equaled 24, so there must be some other way.
Here are the 64 in assending value.
5-5*5-1= -21
5-5*5*1= -20
5-5*5/1= -20
5-5*5+1= -19
5-5-5-1= -6
5-5-5*1= -5
5-5-5/1= -5
5/5-5-1= -5
5-5-5+1= -4
5/5-5*1= -4
5/5-5/1= -4
5/5-5+1= -3
5/5/5-1= -0.8
5/5/5*1= 0.2
5/5/5/1= 0.2
5/5/5+1= 1.2
5-5/5-1= 3
5-5/5*1= 4
5-5/5/1= 4
5-5+5-1= 4
5*5/5-1= 4
5/5*5-1= 4
5+5-5-1= 4
5-5/5+1= 5
5-5+5*1= 5
5-5+5/1= 5
5*5/5*1= 5
5*5/5/1= 5
5/5*5*1= 5
5/5*5/1= 5
5/5+5-1= 5
5+5-5*1= 5
5+5-5/1= 5
5+5/5-1= 5
5-5+5+1= 6
5*5/5+1= 6
5/5*5+1= 6
5/5+5*1= 6
5/5+5/1= 6
5+5-5+1= 6
5+5/5*1= 6
5+5/5/1= 6
5/5+5+1= 7
5+5/5+1= 7
5+5+5-1= 14
5+5+5*1= 15
5+5+5/1= 15
5+5+5+1= 16
5*5-5-1= 19
5*5-5*1= 20
5*5-5/1= 20
5*5-5+1= 21
5*5+5-1= 29
5+5*5-1= 29
5*5+5*1= 30
5*5+5/1= 30
5+5*5*1= 30
5+5*5/1= 30
5*5+5+1= 31
5+5*5+1= 31
5*5*5-1= 124
5*5*5*1= 125
5*5*5/1= 125
5*5*5+1= 126
hjg
(5^2)x(5/5)-1
Inserting ( ) does not help.
448 combinations.
EQ Value
=5-5*(5+1) -25
=5-5*5-1 -21
=5-(5*5)-1 -21
=(5-5*5)-1 -21
=5-(5*5+1) -21
=5-5*5*1 -20
=5-5*5/1 -20
=5-(5*5)*1 -20
=5-(5*5)/1 -20
=5-5*(5*1) -20
=5-5*(5/1) -20
=(5-5*5)*1 -20
=(5-5*5)/1 -20
=5-(5*5*1) -20
=5-(5*5/1) -20
=5-5*5+1 -19
=5-(5*5)+1 -19
=(5-5*5)+1 -19
=5-(5*5-1) -19
=5-5*(5-1) -15
=5-5-5-1 -6
=(5-5)-5-1 -6
=5-(5+5)-1 -6
=5-5-(5+1) -6
=(5-5)-(5+1) -6
=(5-5-5)-1 -6
=5-(5+5+1) -6
=5-5-5*1 -5
=5-5-5/1 -5
=5/5-5-1 -5
=(5-5)-5*1 -5
=(5-5)-5/1 -5
=(5/5)-5-1 -5
=5-(5+5)*1 -5
=5-(5+5)/1 -5
=5-5-(5*1) -5
=5-5-(5/1) -5
=5/5-(5+1) -5
=(5-5)-(5*1) -5
=(5-5)-(5/1) -5
=(5/5)-(5+1) -5
=(5-5-5)*1 -5
=(5-5-5)/1 -5
=(5/5-5)-1 -5
=5-(5+5*1) -5
=5-(5+5/1) -5
=5*(5-5-1) -5
=5/(5-5-1) -5
=5-5-5+1 -4
=5/5-5*1 -4
=5/5-5/1 -4
=(5-5)-5+1 -4
=(5/5)-5*1 -4
=(5/5)-5/1 -4
=5-(5+5)+1 -4
=5-5-(5-1) -4
=5/5-(5*1) -4
=5/5-(5/1) -4
=(5-5)-(5-1) -4
=(5/5)-(5*1) -4
=(5/5)-(5/1) -4
=(5-5-5)+1 -4
=(5/5-5)*1 -4
=(5/5-5)/1 -4
=5-(5+5-1) -4
=5/5-5+1 -3
=(5/5)-5+1 -3
=5/5-(5-1) -3
=(5/5)-(5-1) -3
=(5/5-5)+1 -3
=(5-5)*5-1 -1
=(5-5)/5-1 -1
=5*(5-5)-1 -1
=5/5/5-1 -0.8
=(5/5)/5-1 -0.8
=5/(5*5)-1 -0.8
=(5/5/5)-1 -0.8
=5/(5+5)-1 -0.5
=(5-5)*5*1 0
=(5-5)*5/1 0
=(5-5)/5*1 0
=(5-5)/5/1 0
=5*(5-5)*1 0
=5*(5-5)/1 0
=(5-5)*(5-1) 0
=(5-5)*(5*1) 0
=(5-5)*(5/1) 0
=(5-5)*(5+1) 0
=(5-5)/(5-1) 0
=(5-5)/(5*1) 0
=(5-5)/(5/1) 0
=(5-5)/(5+1) 0
=5*(5-5*1) 0
=5*(5-5/1) 0
=5*(5/5-1) 0
=5/5/(5+1) 0.166666667
=(5/5)/(5+1) 0.166666667
=5/(5*5+1) 0.192307692
=5/5/5*1 0.2
=5/5/5/1 0.2
=(5/5)/5*1 0.2
=(5/5)/5/1 0.2
=5/(5*5)*1 0.2
=5/(5*5)/1 0.2
=5/5/(5*1) 0.2
=5/5/(5/1) 0.2
=(5/5)/(5*1) 0.2
=(5/5)/(5/1) 0.2
=(5/5/5)*1 0.2
=(5/5/5)/1 0.2
=5/(5*5*1) 0.2
=5/(5*5/1) 0.2
=5/(5*5-1) 0.208333333
=5/5/(5-1) 0.25
=(5/5)/(5-1) 0.25
=5/(5+5+1) 0.454545455
=5/(5+5)*1 0.5
=5/(5+5)/1 0.5
=5/(5+5*1) 0.5
=5/(5+5/1) 0.5
=5/(5+5-1) 0.555555556
=(5-5)*5+1 1
=(5-5)/5+1 1
=(5+5)/5-1 1
=5*(5-5)+1 1
=5/5/5+1 1.2
=(5/5)/5+1 1.2
=5/(5*5)+1 1.2
=(5/5/5)+1 1.2
=5/(5+5)+1 1.5
=(5+5)/(5+1) 1.666666667
=(5+5)/5*1 2
=(5+5)/5/1 2
=(5+5)/(5*1) 2
=(5+5)/(5/1) 2
=(5+5)/(5-1) 2.5
=5/(5/5+1) 2.5
=5-5/5-1 3
=(5+5)/5+1 3
=5-(5/5)-1 3
=(5-5/5)-1 3
=5-(5/5+1) 3
=5-5/(5-1) 3.75
=5-5/5*1 4
=5-5/5/1 4
=5-5+5-1 4
=5*5/5-1 4
=5/5*5-1 4
=5+5-5-1 4
=(5-5)+5-1 4
=(5*5)/5-1 4
=(5/5)*5-1 4
=(5+5)-5-1 4
=5-(5-5)-1 4
=5-(5/5)*1 4
=5-(5/5)/1 4
=5*(5/5)-1 4
=5/(5/5)-1 4
=5+(5-5)-1 4
=5-5/(5*1) 4
=5-5/(5/1) 4
=5-5+(5-1) 4
=5/5*(5-1) 4
=5+5-(5+1) 4
=(5-5)+(5-1) 4
=(5/5)*(5-1) 4
=(5+5)-(5+1) 4
=(5-5/5)*1 4
=(5-5/5)/1 4
=(5-5+5)-1 4
=(5*5/5)-1 4
=(5/5*5)-1 4
=(5+5-5)-1 4
=5-(5-5+1) 4
=5-(5/5*1) 4
=5-(5/5/1) 4
=5+(5-5-1) 4
=5-5/(5+1) 4.166666667
=5*5/(5+1) 4.166666667
=(5*5)/(5+1) 4.166666667
=5-5/5+1 5
=5-5+5*1 5
=5-5+5/1 5
=5*5/5*1 5
=5*5/5/1 5
=5/5*5*1 5
=5/5*5/1 5
=5/5+5-1 5
=5+5-5*1 5
=5+5-5/1 5
=5+5/5-1 5
=(5-5)+5*1 5
=(5-5)+5/1 5
=(5*5)/5*1 5
=(5*5)/5/1 5
=(5/5)*5*1 5
=(5/5)*5/1 5
=(5/5)+5-1 5
=(5+5)-5*1 5
=(5+5)-5/1 5
=5-(5-5)*1 5
=5-(5-5)/1 5
=5-(5/5)+1 5
=5*(5/5)*1 5
=5*(5/5)/1 5
=5/(5/5)*1 5
=5/(5/5)/1 5
=5+(5-5)*1 5
=5+(5-5)/1 5
=5+(5/5)-1 5
=5-5+(5*1) 5
=5-5+(5/1) 5
=5*5/(5*1) 5
=5*5/(5/1) 5
=5/5*(5*1) 5
=5/5*(5/1) 5
=5/5+(5-1) 5
=5+5-(5*1) 5
=5+5-(5/1) 5
=(5-5)+(5*1) 5
=(5-5)+(5/1) 5
=(5*5)/(5*1) 5
=(5*5)/(5/1) 5
=(5/5)*(5*1) 5
=(5/5)*(5/1) 5
=(5/5)+(5-1) 5
=(5+5)-(5*1) 5
=(5+5)-(5/1) 5
=(5-5/5)+1 5
=(5-5+5)*1 5
=(5-5+5)/1 5
=(5*5/5)*1 5
=(5*5/5)/1 5
=(5/5*5)*1 5
=(5/5*5)/1 5
=(5/5+5)-1 5
=(5+5-5)*1 5
=(5+5-5)/1 5
=(5+5/5)-1 5
=5-(5-5*1) 5
=5-(5-5/1) 5
=5-(5/5-1) 5
=5*(5-5+1) 5
=5*(5/5*1) 5
=5*(5/5/1) 5
=5/(5-5+1) 5
=5/(5/5*1) 5
=5/(5/5/1) 5
=5+(5-5*1) 5
=5+(5-5/1) 5
=5+(5/5-1) 5
=5+5/(5+1) 5.833333333
=5-5+5+1 6
=5*5/5+1 6
=5/5*5+1 6
=5/5+5*1 6
=5/5+5/1 6
=5+5-5+1 6
=5+5/5*1 6
=5+5/5/1 6
=(5-5)+5+1 6
=(5*5)/5+1 6
=(5/5)*5+1 6
=(5/5)+5*1 6
=(5/5)+5/1 6
=(5+5)-5+1 6
=5-(5-5)+1 6
=5*(5/5)+1 6
=5/(5/5)+1 6
=5+(5-5)+1 6
=5+(5/5)*1 6
=5+(5/5)/1 6
=5-5+(5+1) 6
=5/5*(5+1) 6
=5/5+(5*1) 6
=5/5+(5/1) 6
=5+5-(5-1) 6
=5+5/(5*1) 6
=5+5/(5/1) 6
=(5-5)+(5+1) 6
=(5/5)*(5+1) 6
=(5/5)+(5*1) 6
=(5/5)+(5/1) 6
=(5+5)-(5-1) 6
=(5-5+5)+1 6
=(5*5/5)+1 6
=(5/5*5)+1 6
=(5/5+5)*1 6
=(5/5+5)/1 6
=(5+5-5)+1 6
=(5+5/5)*1 6
=(5+5/5)/1 6
=5-(5-5-1) 6
=5+(5-5+1) 6
=5+(5/5*1) 6
=5+(5/5/1) 6
=5*5/(5-1) 6.25
=5+5/(5-1) 6.25
=(5*5)/(5-1) 6.25
=5/5+5+1 7
=5+5/5+1 7
=(5/5)+5+1 7
=5+(5/5)+1 7
=5/5+(5+1) 7
=(5/5)+(5+1) 7
=(5/5+5)+1 7
=(5+5/5)+1 7
=5+(5/5+1) 7
=5*(5/5+1) 10
=5+5+5-1 14
=(5+5)+5-1 14
=5+(5+5)-1 14
=5+5+(5-1) 14
=(5+5)+(5-1) 14
=(5+5+5)-1 14
=5+(5+5-1) 14
=5+5+5*1 15
=5+5+5/1 15
=(5+5)+5*1 15
=(5+5)+5/1 15
=5+(5+5)*1 15
=5+(5+5)/1 15
=5+5+(5*1) 15
=5+5+(5/1) 15
=(5+5)+(5*1) 15
=(5+5)+(5/1) 15
=(5+5+5)*1 15
=(5+5+5)/1 15
=5+(5+5*1) 15
=5+(5+5/1) 15
=5+5+5+1 16
=(5+5)+5+1 16
=5+(5+5)+1 16
=5+5+(5+1) 16
=(5+5)+(5+1) 16
=(5+5+5)+1 16
=5+(5+5+1) 16
=5*5-5-1 19
=(5*5)-5-1 19
=5*5-(5+1) 19
=(5*5)-(5+1) 19
=(5*5-5)-1 19
=5*5-5*1 20
=5*5-5/1 20
=(5*5)-5*1 20
=(5*5)-5/1 20
=5*5-(5*1) 20
=5*5-(5/1) 20
=(5*5)-(5*1) 20
=(5*5)-(5/1) 20
=(5*5-5)*1 20
=(5*5-5)/1 20
=5*5-5+1 21
=(5*5)-5+1 21
=5*5-(5-1) 21
=(5*5)-(5-1) 21
=(5*5-5)+1 21
=5+5*(5-1) 25
=5*5+5-1 29
=5+5*5-1 29
=(5*5)+5-1 29
=5+(5*5)-1 29
=5*5+(5-1) 29
=(5*5)+(5-1) 29
=(5*5+5)-1 29
=(5+5*5)-1 29
=5+(5*5-1) 29
=5*5+5*1 30
=5*5+5/1 30
=5+5*5*1 30
=5+5*5/1 30
=(5*5)+5*1 30
=(5*5)+5/1 30
=5+(5*5)*1 30
=5+(5*5)/1 30
=5*5+(5*1) 30
=5*5+(5/1) 30
=5+5*(5*1) 30
=5+5*(5/1) 30
=(5*5)+(5*1) 30
=(5*5)+(5/1) 30
=(5*5+5)*1 30
=(5*5+5)/1 30
=(5+5*5)*1 30
=(5+5*5)/1 30
=5+(5*5*1) 30
=5+(5*5/1) 30
=5*5+5+1 31
=5+5*5+1 31
=(5*5)+5+1 31
=5+(5*5)+1 31
=5*5+(5+1) 31
=(5*5)+(5+1) 31
=(5*5+5)+1 31
=(5+5*5)+1 31
=5+(5*5+1) 31
=5+5*(5+1) 35
=(5+5)*(5-1) 40
=5*(5+5-1) 45
=(5+5)*5-1 49
=5*(5+5)-1 49
=(5+5)*5*1 50
=(5+5)*5/1 50
=5*(5+5)*1 50
=5*(5+5)/1 50
=(5+5)*(5*1) 50
=(5+5)*(5/1) 50
=5*(5+5*1) 50
=5*(5+5/1) 50
=(5+5)*5+1 51
=5*(5+5)+1 51
=5*(5+5+1) 55
=(5+5)*(5+1) 60
=5*5*(5-1) 100
=(5*5)*(5-1) 100
=5*(5*5-1) 120
=5*5*5-1 124
=(5*5)*5-1 124
=5*(5*5)-1 124
=(5*5*5)-1 124
=5*5*5*1 125
=5*5*5/1 125
=(5*5)*5*1 125
=(5*5)*5/1 125
=5*(5*5)*1 125
=5*(5*5)/1 125
=5*5*(5*1) 125
=5*5*(5/1) 125
=(5*5)*(5*1) 125
=(5*5)*(5/1) 125
=(5*5*5)*1 125
=(5*5*5)/1 125
=5*(5*5*1) 125
=5*(5*5/1) 125
=5*5*5+1 126
=(5*5)*5+1 126
=5*(5*5)+1 126
=(5*5*5)+1 126
=5*(5*5+1) 130
=5*5*(5+1) 150
=(5*5)*(5+1) 150
=5/(5-5)-1 #DIV/0!
=5/(5-5)*1 #DIV/0!
=5/(5-5)/1 #DIV/0!
=5/(5-5)+1 #DIV/0!
=5/(5-5*1) #DIV/0!
=5/(5-5/1) #DIV/0!
=5/(5/5-1) #DIV/0!
hjg
5-(5*(5+1))
-5+(5*(5+1))
This should get it
(5 - (1/5)) * 5 = 24
The "\" is integer division.
But I have not seem would make a difference because 5/5 = 5\5
and 5\1 = 5/1.
There are a series using "^2" before a sign that do equal 24
5-5+5^2-1
5*5^2/5-1
5/5*5^2-1
5^2-5/5*1
5^2-5/5/1
5^2-5^2/5^2*1
5^2-5^2/5^2/1
5^2-5^2+5^2-1
5^2-5+5-1
5^2*5/5-1
5^2*5^2/5^2-1
5^2/5*5-1
5^2/5^2*5^2-1
5^2+5-5-1
5^2+5^2-5^2-1
5+5^2-5-1
hjg
5\(5+5)*1=2\4
;)
Can't you only put in signs and not add numbers that's cheating
my answer was correct. posted above.
phreebsd said...
This should get it
(5 - (1/5)) * 5 = 24
November 17, 2008 11:15 AM
Question:
?????????????????????
(5 - (1/5)) * 5 = 24
?????????????????????
Are we allowed to change the stated order 5 O 5 O 5 O 1 = 24.
hjg
i think there is something missing or wrong with this puzzle..
maybe the arrangement is incorrect
or theres something missing with the rules..like:
do we have to follow the MDAS?
is it legal to put ()?
To last Anonymous,
If you can't change the order, and you can't add (), and there is a "solution", then there must be a mistake in Kevin Zhu's use of MDAS!!
hjg
the answer is NA the whole point of the puzzle was jsut to make people try combinations and find out that there are none that can match with his equation
unless you use barackets or parentheses
By making and error in MDSA
5 * 5 - 1 / 5 = 24
This is very close to the stated order.
Inserting () to get this...
5 * (5 - 1/5) =
5 * 4.8 = 24
hjg
Sorry, Kevin
This is not a viable solution.
5*0 + 5 * 5 - 1!!!
Zero was not one of the numbers available numbers. The question reads...
"There are four numbers: 5, 5, 5, and 1."
hjg
5*5/5-1=24
Simple as that, ladies and gentlemen
Ummm yeah, that is wrong, try again there brainiac.........
Metka said...
5*5/5-1=24
Simple as that, ladies and gentlemen
November 20, 2008 6:04 AM
I am pretty sure he was being sarcastic.
I cant see a reply from the one who posted this puzzle..
It makes me think that maybe this is just a joke and there is really NO ANSWER to this puzzle..
(5*5)-(5/1)=24
Lame... so you are saying 0 is not a number, plus you didn't say 0 can be part of the operation.
To above, if you want to see the answer look for Kevin's replies.
5*0+5*5-1=24 : D. AD
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