Cube mk2 and WIR

[thehallfamily]

Help my 12 year olds homework has him stumped...give it here I say...I got a B at O'level. But help I can't do it either.......help me out, I don't want to look a ninny in front of him!

 

You have to make the answers 1-20 using 4x4s. You must use all 4of the 4s and can only use + - x and divide. We managed about 8 of them...but can do no more!

 

e.g 16 = (4x4) + (4-4)

 

Go on I know you can do it!

[Lesley]

....I'm going for a lie down

 

I know I like numbers but my head is hurting already

[Guest]

(edit - ahhh!! - I didn't read the question properly!!!! ignore the following!!) - you have to use excactly four 4's for each answer?

 

 

1 = (4x4)/(4x4)

 

2 = (4+4)/4

 

3 = (4+4+4)/4

 

4 = (4+4) -4

 

5 = 4 + {(4+4)/(4x4)}

 

6 = (4+4) - {(4+4)/4}

 

7 = 4 + {(4+4+4)/4}

 

8 = 4+4

 

9 = (4+4+4) - {(4+4+4)/4}

 

10 = (4+4+4) - {(4+4)/4}

 

(and so on up to 20 - it would be cheating to do them all for him!)

 

 

(of course - there are a thousand and one differend combinations of the above)

Edited March 31, 2006 by Guest

[Mrs Frugal]

I hate maths but usually get to help my poor boys when they get stuck. Can you give us the ones you've already done as more examples?

[thehallfamily]

well..

 

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

15 = (4x4) - (4/4)

17 = (4x4) + (4/4)

[Louise]

I'm taking this home for the weekend and I may ask my dad to do it he is magic with numbers

 

Mind you if I tell him it is someones homework he may not play ball

[thehallfamily]

Don't worry I will not give Oliver the answers...just needed to know it was possible, and be able to give him a jab in the right direction.

 

Its the first homework he has got since starting secondary school in September that he has been unable to complete....first time he'd asked me for help too

[Guest]

Can you tell us which ones you have already?

[Guest]

I don't think it can be done wth just +, -, * and / - so a couple are cheats!

 

 

1 = (4+4)/(4+4)

2 = 4/4 +4/4 or (4*4)/(4+4)

3 = (4+4+4)/4

4 = 4*(4-4) +4

5 = [4*4 +4 ] / 4

6 = [(4+4) /4] +4

7 = (4+4) - (4/4)

8 = (4*4) - (4+4)

9 = 4/4 + (4+4)

10 = (44-4)/4 44 must be OK?

11 = 44 / (sqrt 4 + sqrt 4) where sqrt = square root

12 = 4 + 4 + sqrt 4 + sqrt 4

13 = 4!/(sqrt 4) + 4/4 where 4! = 4 factorial=24 (cheating again?)

14 = (4+4+4) + sqrt 4

15 = (44/4)+4

16 = (4*4*4)/4

17 = (4*4 + 4/4

18 = (4*4 + 4) - sqrt 4

19 = (4! - 4) - 4/4

20 = (4! - 4) / 4/4

 

 

there! I knew that maths degree would come in handy one day...

 

but let him work it out for himself!

 

Phil

[thehallfamily]

1 = (4x4)/(4x4)

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

3 = (4+4+4)/4

4

5

6

7

8 = (4x4) –4-4

9= (4/4) +4+4

10

11

12

13

14

15 = (4x4) - (4/4)

16 = (4x4) + (4-4)

17 = (4x4) + (4/4)

18

19

20

 

Was as far as we got from memory.......homework is at home...!

[Guest]

Using the rules(!) - this is what I have so far....

 

(4+4)/(4+4) = 1

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

(4+4+4)/4 = 3

((4-4)*4)+4 = 4 (*corrected*)

((4*4)+4)/4) = 5

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

(4+4)-(4/4) = 7

(4-4)+(4+4) = 8

(4/4)+(4+4) = 9

(4-(4/4))*4 = 12

(4x4)-(4/4) = 15

(4/4)*(4*4) = 16

(4x4)+(4/4) = 17

(4+(4/4))*4 = 20

Edited March 31, 2006 by Guest

[Guest]

GRD - your no.4 doesn't work... ((4/4)*4)+4 = 8

 

but your 20 and 12 are better than mine!

 

Phil

[thehallfamily]

Hey thanks for all the help, won't mention my maths skills to my husband since I do his company account keeping!

[Cinnamon]

Hey thanks for all the help, won't mention my maths skills to my husband since I do his company account keeping!

 

HA!

Same here - I am terrible at maths,but have somehow found myself employed as our company accountant

[Guest]

GRD - your no.4 doesn't work... ((4/4)*4)+4 = 8

 

but your 20 and 12 are better than mine!

 

Phil

 

Thanks Phil - have now corrected. I agree that some cannot be done unless bending the rules. I think some solutions like your number 10 must be allowed - I can't see a way of doing it otherwise.

[Cate in NZ]

Aaaaaagh.

I've definitely stumbled onto the wrong thread. Off for a lie down in a darkened room now

[Hellcat]

Hand up'Please, sir, I don't understand the question'.

 

What are you all going on about? I don't even understand how it works! no, Don't try to explain, I'm sure I have a form of number dyslexia. I go glazed and I'm told you can watch the shutters come down over my eyes when numbers happen!

[myles]

avoiding the 44 cheat 10 = (4!/sqrt4)-(4/sqrt4)

[Guest]

So we're using square roots now?

 

My version: (4+4+4)-sqrt(4) = 10

[Hellcat]

arggh! My brain hurts!