c4countdown

Posted: **Sat Jun 13, 2009 10:05 pm**

Yes, it's that puzzle that everyone has already done, it's Four 4s!

You have to use all four 4s to make every number from 1 to 100. Pretty simple.

You can use most functions; if they are dubious, ask about them.

Banned functions:

Integer brackets []
Trigonononononometric thingies sin cos tan etc.
Powers
Stuff like that.

First person to get 1 wins a signed VFSMB.

Posted: **Sat Jun 13, 2009 10:13 pm**

Sorry; what is the significance of 'integer' brackets [] as opposed to ()?

Posted: **Sat Jun 13, 2009 10:19 pm**

Daniel O'Dowd wrote:Sorry; what is the significance of 'integer' brackets [] as opposed to ()?

Integer brackets ignore decimals, for example [sqrt(sqrt(4))] would be the integer of sqrt 2, ie. 1.

Posted: **Sat Jun 13, 2009 10:22 pm**

Kai Laddiman wrote:First person to get 1 wins a signed VFSMB.

1 = (4/4)*(4/4)

Posted: **Sat Jun 13, 2009 10:57 pm**

Matt Morrison wrote:
Kai Laddiman wrote:First person to get 1 wins a signed VFSMB.
1 = (4/4)*(4/4)

2= (4/4)+(4/4)

Posted: **Sat Jun 13, 2009 10:59 pm**

Steve Durney wrote:
Matt Morrison wrote:
Kai Laddiman wrote:First person to get 1 wins a signed VFSMB.
1 = (4/4)*(4/4)
2= (4/4)+(4/4)

3= (4*4-4)/4

Posted: **Sat Jun 13, 2009 11:20 pm**

4 = 4

Posted: **Sat Jun 13, 2009 11:23 pm**

Charlie Reams wrote:4 = 4

The rules say you need to use all four fours.

So (4-4)x4+4 = 4

Posted: **Sat Jun 13, 2009 11:24 pm**

Howard Somerset wrote:
Charlie Reams wrote:4 = 4
The rules say you need to use all four fours.

So (4-4)x4+4 = 4

You've used five 4s...

Posted: **Sat Jun 13, 2009 11:25 pm**

Michael Wallace wrote:
Howard Somerset wrote:
Charlie Reams wrote:4 = 4
The rules say you need to use all four fours.

So (4-4)x4+4 = 4
You've used five 4s...

You've used a 5.

Posted: **Sat Jun 13, 2009 11:26 pm**

Michael Wallace wrote:
Howard Somerset wrote:
Charlie Reams wrote:4 = 4
The rules say you need to use all four fours.

So (4-4)x4+4 = 4
You've used five 4s...

No. I've used only four 4s. The fifth is the result.

Posted: **Sat Jun 13, 2009 11:27 pm**

Howard Somerset wrote:No. I've used only four 4s. The fifth is the result.

It would seem my 'humour' is wasted here

Posted: **Sat Jun 13, 2009 11:28 pm**

Michael Wallace wrote:
Howard Somerset wrote:No. I've used only four 4s. The fifth is the result.
It would seem my 'humour' is wasted here

We'd have difficulty when we get to 44.

Posted: **Sat Jun 13, 2009 11:30 pm**

Looking ahead a little:

Is sqrt allowed?
Is factorial allowed?

Posted: **Sat Jun 13, 2009 11:38 pm**

May the fours be with you.

Posted: **Sat Jun 13, 2009 11:40 pm**

Am I allowed to go for the next one too?

If so, (4x4+4)/4 = 5

Posted: **Sat Jun 13, 2009 11:47 pm**

((4 + 4) / 4) + 4 = 6

Posted: **Sat Jun 13, 2009 11:51 pm**

4 + 4 - 4/4 = 7

Posted: **Sat Jun 13, 2009 11:54 pm**

I'm not afraid to admit that 14 is stumping me.

A clear definition of which functions we can and can't use might help?

Posted: **Sat Jun 13, 2009 11:56 pm**

Matt Morrison wrote:I'm not afraid to admit that 14 is stumping me.

A clear definition of which functions we can and can't use might help?

If it's allowed, then 4 x 4 - 4 + sqrt(4) = 14

Posted: **Sat Jun 13, 2009 11:58 pm**

Howard Somerset wrote:
Matt Morrison wrote:I'm not afraid to admit that 14 is stumping me.

A clear definition of which functions we can and can't use might help?
If it's allowed, then 4 x 4 - 4 + sqrt(4) = 14

Cool. I'd avoided square roots, but they're officially in now. Thumbs up for factorials too.

Posted: **Sun Jun 14, 2009 12:01 am**

I'm sure that when I did this at school in 1953 we used sqrt and factorial. And I think it was somewhere in the 30s where we got stuck.

After allowing [], which Kai has outlawed, pretty well anything becomes possible.

We also used concatenation, which Kai needs to rule upon, e.g. 44 + 44 = 88

Posted: **Sun Jun 14, 2009 12:04 am**

Howard Somerset wrote:
Michael Wallace wrote:
Howard Somerset wrote:No. I've used only four 4s. The fifth is the result.
It would seem my 'humour' is wasted here
We'd have difficulty when we get to 44.

44 + 4-4 = 44

Posted: **Sun Jun 14, 2009 12:31 am**

(4 + 4) * 4 / 4 = 8

Posted: **Sun Jun 14, 2009 12:38 am**

4 + 4 + 4/4 = 9

Posted: **Sun Jun 14, 2009 12:48 am**

(4-(4/4))! + 4 = 10

Posted: **Sun Jun 14, 2009 12:58 am**

4+((4!+4)/4)=11

Posted: **Sun Jun 14, 2009 1:00 am**

4 x 4 - sqrt(4 x 4) = 12

Posted: **Sun Jun 14, 2009 1:08 am**

4!−(44/4)=13

Posted: **Sun Jun 14, 2009 1:09 am**

(4!4+4!+4)/4=13

Posted: **Sun Jun 14, 2009 1:13 am**

4!/4 + 4 + 4 = 14

Posted: **Sun Jun 14, 2009 1:14 am**

Jon O'Neill wrote:(4!4+4!+4)/4=13

Second 4 should be removed. Nice one.

Posted: **Sun Jun 14, 2009 1:14 am**

(4*4) - (4/4) = 15

Posted: **Sun Jun 14, 2009 1:17 am**

4x4x4/4=16

Posted: **Sun Jun 14, 2009 1:19 am**

4x4+4/4=17

Posted: **Sun Jun 14, 2009 1:39 am**

Daniel O'Dowd wrote:4!−(44/4)=13

(4!+4!+4)/4 without concatenation

Posted: **Sun Jun 14, 2009 1:40 am**

4*4 +(4 /sqrt4 )=18 4!-4-(4/4)=19

Posted: **Sun Jun 14, 2009 1:44 am**

4 x (4 + 4/4) = 20

Posted: **Sun Jun 14, 2009 1:47 am**

Matt Morrison wrote:(4!+4!+4)/4 without concatenation

I think that's what Jono was trying to say. He put an extra 4 in by mistake.

Posted: **Sun Jun 14, 2009 1:48 am**

4!-4-4+4=20 4!-4 +(4/4)=21 4*4+4+sqrt4=22

Posted: **Sun Jun 14, 2009 1:53 am**

You missed 18:

4!-Sq4-Sq4-Sq4=18

Posted: **Sun Jun 14, 2009 1:54 am**

Daniel O'Dowd wrote:You missed 18:

4!-Sq4-Sq4-Sq4=18

Liam Tiernan wrote:4*4 +(4 /sqrt4 )=18

Posted: **Sun Jun 14, 2009 1:54 am**

((4!*4)-4)/4=23

Posted: **Sun Jun 14, 2009 1:56 am**

4! - 4/sqrt(4x4) = 23

4! x 4/sqrt(4x4) = 24

4! + 4/sqrt(4x4) = 25

Posted: **Sun Jun 14, 2009 1:57 am**

(44+4)/sqrt4=24

Posted: **Sun Jun 14, 2009 1:59 am**

((44/4)*sqrt4)+4=26

Posted: **Sun Jun 14, 2009 2:05 am**

4!+4-(4/4)=27

Posted: **Sun Jun 14, 2009 2:09 am**

4!+4+4-4=28 4!+4+(4/4)=29 4!+4+(4/sqrt4)=30

Posted: **Sun Jun 14, 2009 7:58 am**

Howard Somerset wrote:Looking ahead a little:

Is sqrt allowed?
Is factorial allowed?

Yup and yup.

Posted: **Sun Jun 14, 2009 8:02 am**

OK then, the following functions are allowed:

sqrt
factorial ! (sorry Charlie) and any variants of it
concatenation (although it is possible to get them all without it

)

And, yeh, I think that's it. And by factorial variations, well, Wikipedia!

Posted: **Sun Jun 14, 2009 8:04 am**

Er, I'm having trouble keeping up with all of these solutions (I sleep), but I think we've got all of the ones up to 30, no?

Posted: **Sun Jun 14, 2009 8:37 am**

Kai Laddiman wrote:
Howard Somerset wrote:Looking ahead a little:

Is sqrt allowed?
Is factorial allowed?
Yup and yup.

Glad to hear that. I think this puzzle is made possible because sqrt(4) is an integer.
But I was concerned when you outlawed powers, because sqrt is simply a power of 0.5. Glad you've allowed this exception.

Liam Tiernan wrote:4!+4+4-4=28 4!+4+(4/4)=29 4!+4+(4/sqrt4)=30

Good to see you didn't carry on too much further after I'd gone to bed. I was expecting to see many more done by this morning.

Posted: **Sun Jun 14, 2009 8:43 am**

Another couple of questions:

Can we have decimal points? e.g. 4/.4 = 10
Can we have recurring decimals? e.g.

Code: Select all

   .
4/.4   = 9

If so, then

Code: Select all

        .
4! + 4/.4 - sqrt(4) = 31

Posted: **Sun Jun 14, 2009 8:53 am**

Howard Somerset wrote:
Matt Morrison wrote:(4!+4!+4)/4 without concatenation
I think that's what Jono was trying to say. He put an extra 4 in by mistake.

Thanks Howard. Drunk.

Posted: **Sun Jun 14, 2009 8:57 am**

Howard Somerset wrote:Another couple of questions:

Can we have decimal points? e.g. 4/.4 = 10
Can we have recurring decimals? e.g.
Code: Select all
   .
4/.4   = 9
If so, then
Code: Select all
        .
4! + 4/.4 - sqrt(4) = 31

Er, if you absolutely have to, then use decimal points. Although it's possible without them...

Posted: **Sun Jun 14, 2009 8:57 am**

Jon O'Neill wrote:
Howard Somerset wrote:
Matt Morrison wrote:(4!+4!+4)/4 without concatenation
I think that's what Jono was trying to say. He put an extra 4 in by mistake.
Thanks Howard. Drunk.

YW. Guessed so.

Posted: **Sun Jun 14, 2009 10:15 am**

We were given this at school to occupy us for half an hour while our teacher did his pools. I got stuck at (I think) 33. Years later, lying on a beach, I suddenly thought "Decimals! And recurring decimals!!" (I have good holidays.)

After that I had another bash and kept a dog-eared piece of paper with all I could get up to about 500. I'm proud to say that when I discovered the internet I'd got every single one that's possible without using gamma functions and natural logarithms.

Posted: **Sun Jun 14, 2009 10:34 am**

Next one's easy (4*4)+(4*4)=32

Posted: **Sun Jun 14, 2009 11:09 am**

Apologies Jono, didn't notice yours was for 13 too, not trying to steal your thunder!
But yeah if Kai says it can be done without concatenation and decimals, let's do it without. I'm still stuck on 31.

Posted: **Sun Jun 14, 2009 11:17 am**

Next one..........not so easy.

c4countdown

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