Help with algebra maths problem please.

[Notplannedforthis]

Can anyone help with this maths problem?

I get the answer to be 11 as I do the 1x2 inside the brackets first to make the problem 8/2x2+3 = 4 x 2 + 3 = 8 + 3 = 11

However 11 is not an option.

Whoops. Should have previewed that, some of the math symbols got converted into formatting, sorry!

I have replaced the asterisk required in Excel with the letter "x" for the purposes of this post. Hopefully this will work

"=8/4x2" in Excel gets you 4. There are no implied brackets. To process the 4x2 first you would need to put in "=8/(4x2)".
But, 8+4x2 would be 16, because with the precedence rules, the multiplying happens before the adding.

@YankeeDad Did you look at the original problem?
UK maths and USA maths are the same, the whole scientific world would fall to pieces if basic maths like this could mean different things in different countries. It's bad enough the USA still use imperial for some things rather than SI units.

Look at noblegiraffe's image to see the explanation.

It's not that precedence rules are different in different places, I don't think.

I think it's just a really poorly written/ambiguous question.

The rules are totally clear, but what is not clear by using a division symbol right next to brackets is whether the writer is asking for those brackets to be on the bottom of the division fraction, or the top of it. It's just not written properly with standard maths conventions, and I don't think a good mathematician would leave it written like that.

I can see arguments for both 5 and 11, depending on what you assume about division and fractions written like that.

Normally you would not use the convesion of a division sign and the convention of things written next to brackets as being multiplied at the same time, without clarifying what you mean.

Yankee dad divide and multiply have equal precedence here too. Obviously. You think we have different maths here or something? A special UK version of excel?

Mathematicians would normally use fractions rather than the division sign to make it more clear, and a mathematician would see the 2(2x1) as a group.

Calculators rigidly applying BIDMAS instead of looking at the 'feel' of the thing is why kids get -1^2 wrong when they do it on their calculator.

On reflection I think the ambiguity is part of the question in a sense, and bring able to say 'well I can come up with 5 or 11 but only 5 is an option so it must be that' might be part of what they're looking for.

@titchy @TeenPlusCat

Apologies, I looked at the problem as worded in the post, ie 8/2x2+3, which I still think would be 11, but I did not click on the image, nor did I notice that this was described in the post as being already one step past the problem in the image, which upon clicking showed up as 8/2(1x2)+3.

Given how it is expressed, I can see why it would be 5. 2(1x2) suggests to resolve that into a four before dividing into eight. But, I also agree that it is a poorly expressed problem with some ambiguity. Had 11 and 5 both been given as possible answers, this would have been borderline unfair.

Is it ambiguous though? Isn't it testing if kids know that 2(2x1) is different from 2 x (2 x 1)?

Yep, the answer is 5. (Ex primary school teacher with A level maths here)

Before seeing a problem like this one I always thought of 2(2x1) as a sort of shorthand for 2x (2x1) that means exactly the same thing, just like "ab" is a shorthand for "a times b". But I guess this problem shows it can be used to mean something slightly different in that omitting the first "x" makes that multiplication operation take precedence over the division operation to its left ...

So elegant.

From Google

8/2x2+3 =
((8 / 2) x 2) + 3 = 11

4 x 2 + 3 =
(4 x 2) + 3 = 11

8 + 3 = 11

@Hawkins001 that wasn't the original problem however.

My bad, I did not read all the parts properly

From google

8 ÷ (2(2x1)) + 3

Then Google changed it too:

(8 / (2 * (2 x 1))) + 3 = 5

Not sure if that's any use, but that's my attempt

noblegiraffe has given a very good explanation. No second pair of brackets is needed.

I get 5

If you were writing it in words you could say:

Eight divided by two lots of two times 1, plus three.

That would reduce to:

Eight divided by four, plus three.

Which would give:

2 plus three.

Answer 5.

I'm not sure why Google added the extra ones, but I presume they are needed ?

No they aren't needed if you know maths.
But if you know a bit of maths they might be helpful .
However as this question was for 11+ they would be testing that the child did know maths, hence no extra brackets.

Sorry to resurrect my old thread, but DH showed me this today.

It seems I'm not the only one that has struggled with this type of question!

☺ thanks

So whats your final answer.....