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Maths Puzzle- The 4 4's
OK so here is a challenge that will certainly make you think.
Can you make the numbers 0 to 20 by using just 4 lots of the number 4 in varying combinations?
"But how?" You ask!
You can use any of the following
+
-
x
/
4
.4
44
^
(that little ^ means "power of")
No use of ! (factorial) or logs allowed.
I'll give you an example to help you get it
12= (4x(4-(4/4)))
Sorry, I know it's hard to write maths stuff on here!
The trickiest ones are 4,6,13,14,19
There is more than one solution, I will post the answers in a day or so.
Yours
Mr Mathematics
P.S. I hope someone else can solve this, it took me a little while to think on (I do have the answers)
Last edited by joebeanyuk; 05-26-2003 at 01:46 PM.
He was just a normal man 'till this cheeky little hormone called testosterone kicked in
http://www.xtcf.com
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http://www.flipshark.com
This is kind of easy, just time consuming.
1= (4/4)
2= (4/4)+(4/4)
3= (4 -(4/4))
4= (4 X (4/4))
5= (4 +(4/4))
6= (4 + ((4/4)+(4/4)))
Okay I'm bored so I'll just start doing the "hard ones"
13= ((4X4) + (4/4)) - 4
14= (4X4) - ((4/4) + (4/4))
19= ((4X4)- (4/4)) + 4
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Loop Junkie
Well...looks like I'm bored since I actually tried this:
0 = 4 + 4 - 4 - 4
1 = (4/4)(44/44)
2 = (4/4) + (44/44)
3 = ((4x4) - 4)/4
4 = ((44 - 4)/4)/4
5 = ((4x4) + 4)/4
6 = ((4x4)(.4)) - .4
7 = (4 + 4) - (4/4)
8 = ((4x4)/4) + 4
9 = (4/.4) - (4/4)
10 = (44/4) - (4/4)
11 = (44/4)(4/4)
12 = (44/4) + (4/4)
13 =
14 = (44x.4) + .4 - 4
15 = (4x4) - (4/4)
16 = ((44 - 4)/4) - 4
17 = (4x4) + (4/4)
18 = (4/.4) + 4 + 4
19 = (44/4) + 4 + 4
20 = ((44 - 4)/4) + 4
I only had about 15 minutes to do these....I'll give #13 another shot when I get back from lunch.
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Yeah but that's not using 4 lots of the number 4. You have used more or less than. In each case you have to use the number 4, 4 times. So chew on that one if you will
OK I will give you another example
19= (((4+4)-.4)/.4)
That's how it supposed to be done, you see, four lots of four. Using the number 4, 4 times to make 19.
He was just a normal man 'till this cheeky little hormone called testosterone kicked in
http://www.xtcf.com
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Loop Junkie
Originally posted by flipshark
This is kind of easy, just time consuming.
1= (4/4)
2= (4/4)+(4/4)
3= (4 -(4/4))
4= (4 X (4/4))
5= (4 +(4/4))
6= (4 + ((4/4)+(4/4)))
Okay I'm bored so I'll just start doing the "hard ones"
13= ((4X4) + (4/4)) - 4
14= (4X4) - ((4/4) + (4/4))
19= ((4X4)- (4/4)) + 4
I think the idea is that you have to use exactly four numbers...which makes it a lot tougher. Other wise you could just add (4/4) + (4/4)..... until you got them all
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Originally posted by calpomatt
Well...looks like I'm bored since I actually tried this:
0 = 4 + 4 - 4 - 4
1 = (4/4)(44/44)
2 = (4/4) + (44/44)
3 = ((4x4) - 4)/4
4 = ((44 - 4)/4)/4
5 = ((4x4) + 4)/4
6 = ((4x4)(.4)) - .4
7 = (4 + 4) - (4/4)
8 = ((4x4)/4) + 4
9 = (4/.4) - (4/4)
10 = (44/4) - (4/4)
11 = (44/4)(4/4)
12 = (44/4) + (4/4)
13 =
14 = (44x.4) + .4 - 4
15 = (4x4) - (4/4)
16 = ((44 - 4)/4) - 4
17 = (4x4) + (4/4)
18 = (4/.4) + 4 + 4
19 = (44/4) + 4 + 4
20 = ((44 - 4)/4) + 4
I only had about 15 minutes to do these....I'll give #13 another shot when I get back from lunch.
OK the ones that are wrong are:
1
2
4
10
11
12
13
14
16
19
20
You did not use the number 4, 4 times, you just used 4 a lot of times to get what you wanted. You cannot use the number 4 more or less than 4 times to get any number. So have a bit more of a thinker on that
He was just a normal man 'till this cheeky little hormone called testosterone kicked in
http://www.xtcf.com
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Originally posted by calpomatt
I think the idea is that you have to use exactly four numbers...which makes it a lot tougher. Other wise you could just add (4/4) + (4/4)..... until you got them all
That is exactly right, heh someone gets it. Answers to be posted in about 12 hours time
He was just a normal man 'till this cheeky little hormone called testosterone kicked in
http://www.xtcf.com
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Loop Junkie
Ohhh....ok. I thought you were saying we were supposed to use 4, .4, and 44 exactly four times....not just the digit 4. Here it is with a few corrections:
0 = 4 + 4 - 4 - 4
1 = (4/4)(4/4)
2 = (4/4) + (4/4)
3 = ((4x4) - 4)/4
4 = ?
5 = ((4x4) + 4)/4
6 = ((4x4)(.4)) - .4
7 = (4 + 4) - (4/4)
8 = ((4x4)/4) + 4
9 = (4/.4) - (4/4)
10 = (4/4)(4/.4)
11 = ?
12 = ?
13 = ?
14 = ((4 - .4)(4)) - .4
15 = (4x4) - (4/4)
16 = 4 + 4 + 4 +4
17 = (4x4) + (4/4)
18 = (4/.4) + 4 + 4
19 = ((4+4)-.4)/.4
20 = (4/.4) + (4/.4)
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Retired Mod
ones not gotten
4 = 4x(4-4)+4
11 = (44/(squareroot(4 * 4)))
it took three people to come up with these
edit - can I use square root?
Last edited by aversion; 05-26-2003 at 08:05 PM.
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Loop Junkie
Originally posted by aversion
4 = 4x(4-4)+4
How did I not think of that! Must be a little slow after 3 days of wine tasting.
No square roots though....just the symbols he wrote above.
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Retired Mod
well
12 = (4+0.4+0.4)/0.4
still stuck on 13 though
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BradyWhite.net
mmm... 13... let me think
(4^4) = 256
(4*4) = 16
(4*.4) = 1.6
(4/.4) = 10
(4^.4) = 1.7411011265
(4+4) = 8
(4-.4) = 3.6
(44^.4) = 4.543401013
13 = well... (4-.4)*(4-.4) = 12.96 (if you round it = 13 ) ?? (I know its wrong but best I could do..
11 = (4/.4)+(4/4)
a few more ideas...
(4*4)-.4 = 15.6 ... so if we *could* do this...
(4*4)-.4-(4-.4) = 13
hmmm...
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Originally posted by aversion
ones not gotten
4 = 4x(4-4)+4
11 = (44/(squareroot(4 * 4)))
it took three people to come up with these
edit - can I use square root?
but you can use ^0.5 which is the same thing.
*thinks*
4^(4/(4+4))
gives you two, but you ain't got no numbers left.
i'm stuck on 11 and 13. annoying as..... a crying baby on a longhaul flight!!!
edit: is 44 definately 2 uses of the number 4?
//jgo
Last edited by jgo; 05-27-2003 at 04:03 AM.
jgo: pleased to meet you.
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Well here are the answers
0= (4-4)+(4-4)
1= (4x4)/(4x4)
2= (4/.4)-(4+4)
3= ((4x4)-4)/4
4= 4x(4^(4-4))
5= ((4x4)+4)/4
6= (4x.4)+(4+.4)
7= (4+4)-(4/4)
8= ((4x4)/4)+4
9= (4+4)+(4/4)
10= (4/.4)+(4-4)
11= (4/.4)+(4/4)
12= 4x(4-(4/4))
13= ((4-.4)/.4)+4
14= ((4x.4)+4)/.4
15= (4x4)-(4/4)
16= (4+4)+(4+4)
17= (4x4)+(4/4)
18= (4/.4)+(4+4)
19= ((4+4)-.4)/.4
20= (4/.4)+(4/.4)
There is more than one solution to quite a few of these.
By the way you can't use square root, as it's not technically 4. You can use 4th root, if you needed it. That means you can't have ^ unless it is ^4.4 ^4-4 etc
Good attempts though, it did take a while to come up with 13.
Last edited by joebeanyuk; 05-27-2003 at 04:13 AM.
He was just a normal man 'till this cheeky little hormone called testosterone kicked in
http://www.xtcf.com
-
Originally posted by joebeanyuk
11= (4/.4)+(4/4)
13= ((4-.4)/.4)+4
now they just seem obvious!
oh well - i didn't do too bad
0 = (4+4)+(4-4)
1 = 44/44
2 = (4/4) + (4/4)
3 = (4+4+4)/4
4 = 4*(4^(4-4))
5 = ((4*4)+4)/4
6 = ((4*4)*0.4) - 0.4
7 = (4+4)-(4/4)
8 = (4*4)-(4+4)
9 = (4/4)+4+4
10 = (44-4)/4
11 = ?
12 = (44+4)/4
13 = ?
14 = ((4-.4)*4) - .4
15 = (4*4)-(4/4)
16 = 4+4+4+4
17 = (4*4)+(4/4)
18 = (44*0.4)+0.4
19 = ((4+4)-.4)/.4
20 = 4*(4+(4/4))
//jgo
jgo: pleased to meet you.
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BradyWhite.net
blast, I was soo close... 3.6 / .4 = 9!!! DAMG IT!
at least I got 11 that makes me happy.
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