Apply any mathematical function

S

Sune Fibaek

Hi

I have a bit of a tricky question.

Three identical integers (ex. 3, 3, 3). Apply any mathematical funtion to
each to make the sum=6. In the case of 3: 3*3-3=6 or -3+3*3. The integers are
from 1 through 9. Always in identical triplets.

Obviously this is one of those annoying viral emails. I thought I might give
it a shot with Excel rather than to just brute force it. Got stuck though.

Any thoughts?

/Sune
 
P

Pete_UK

When I first came across this type of problem (about 20 years ago) it
was to use 4 identical digits (eg nines) to produce all the numbers
from 1 to 20 using any of the four main arithmetic operations (i.e.
not exponentiation, factorials etc). Brackets were allowed, though.
The solutions called for a bit of lateral thinking, and I'm not sure
if Excel is up to that.

Pete
 
S

Sune Fibaek

Pete_UK said:
When I first came across this type of problem (about 20 years ago) it
Click to expand...

I'll admit it is not exactly new...
The solutions called for a bit of lateral thinking, and I'm not sure
if Excel is up to that.
Click to expand...

I came to that conclusion as well. Especially given that apparently this is
an acceptable solution (according to the sender):

2^4-2^3-2=6

Whereas this:

2^2+2=6

Is not. That leaves me with litteraly an infinite number of possible
solutions. But also makes it quite easy given that then this is also possible:

=SUM((8-LOG(100));(8*LOG(1));(8*LOG(1))).

I figure that if ^4 is a mathematical function (as opposed to power being
the funtion and 4 being the value of the funtion) then log(100) is a funtion
as well.

And thus ends yet another unproductive ½ hour at work :)

/Sune
 
P

Pete_UK

Well, I'm not sure how you (or the sender) can justify:

2^4-2^3-2=6

if you are meant to be using only three 2s, especially as:

2 + 2 + 2 = 6

2^4 is just shorthand for 2 * 2 * 2 * 2, so how can that be allowed?

Pete
 
B

Bernie Deitrick

Sune,

Sub Find6()
Dim Op1 As Variant
Dim Op2 As Variant
Dim Op3 As Variant
Dim myStr As String
Dim Result As Double
Dim AllOp As Variant
Dim i As Integer
Dim j As Integer
Dim k As Integer

AllOp = Array("+", "-", "*", "/", "^")

On Error GoTo NoGood
For i = 1 To 9
For Each Op1 In AllOp
For Each Op2 In AllOp
For Each Op3 In AllOp
myStr = Op1 & i & Op2 & i & Op3 & i
Result = Evaluate(myStr)
If Result = 6 And Result = Int(Result) Then
MsgBox myStr & " = 6"
GoTo Found6 'Comment out this line to see all solutions
End If
KeepGoing:
Next Op3
Next Op2
Next Op1
Found6:
Next i

Exit Sub
NoGood:
Resume KeepGoing

End Sub
 
B

Bernie Deitrick

Bob,

Why do you think it seems that way? Did you try the code? I certainly did.... and I did not get
stuck.

HTH,
Bernie
MS Excel MVP
 
B

Bob I

The code doesn't stop kind of stuck , there just isn't a solution for 1
kind of stuck.
 
F

Frederik

You really need a computer to solve the puzzle???
Do it yourself!
Here is the solution for 1:

(1+1+1)!

where ! means the function 'fact'.
 
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