maths problem

[rsvp]

have just seen this and would welcome thoughts from greater brains than mine!
4x4+4x4+4-4x4 = ?.......I got20 but has been a long time since I was at school.
My reasoning is .....
(4x4)+(4x4) = 32
32+4= 36
- (4x4) 16 therefore answer is 36-16 =20

Very happy to be proven wrong but would love to know why!!! thank you

[MarkRae]

You are correct.

[rsvp]

thank you MarkRae

[mike11111]

This is an old one and goes back to my grammar school days. The point of the joke was that the setter had omitted to include brackets, so you can come up with a myriad of answers, depending upon where you suppose the missing brackets to be placed.

[sunny-dave]

20 is right - BIDMAS says so

[rsvp]

Mie and S dave - thanks to you too

[rsvp]

typo - sorry Mike and ....

[Prudie]

It is correct and it's not random where you put the brackets, you are probably remembering the BODMAS rule (which the modernists now call something more trendy). basically you have to perform the operations in order - brackets, of,division, multiplication, addition, subtraction.

[furrypusscat]

Ideally it should show brackets.

[mike11111]

BIDMAS, whatever happened to BODMAS?

The other one current at the time was that you could prove by erroneous algebraic logic that 1 = 2

[joeluke]

320 is correct answer

[rsvp]

prudie and furrypusscat - I admit to being a bit flummoxed at first but thought I remembered my maths rules - (we were still witing on slates when I went to school) so as an old person I'm pleased with the confirmation from abers. thank you

[Prudie]

Are you on a roll with controversial posts joe?

[joeluke]

4x4=16+4=20x4=80+4=84-4=80x4=320

What's controversial about that prudie?

[mike11111]

Slates? You were privileged. We were writing on the hides of woolly mammoths and sabre-toothed tigers.

[rsvp]

Mike - love the answer x
joeluke - see how you've got there but I remember maths principles as being what prudie posted.

[ChuckFickens]

Joe apparently failed maths then. it's (obviously, as has been stated)

(4*4)+(4*4)+4-(4*4)=20

[Prudie]

It's controversial because several posters have already given the correct answer of 20 and why it's right!

[mike11111]

Prudie et al are boringly correct. I don't know if any of you have come across a recent brand of mathematical puzzle published in the more quality press, wherein to solve the question BODMAS must be strictly ignored.

[ChuckFickens]

Surely that'll be a maths puzzle where you have to give an incorrect answer to solve it then?

[joeluke]

My answer is correct, there are no brackets

How can the answer be 20 when the brackets could be anywhere in the sum?

i.e. 4x(4+4)x4+(4-4)x4 =512