What Is The Answer?

[10ClarionSt]

My granddaughter asked a question from her maths homework, as follows:
The square root of a number is 3. What is the square of the number? I said 81 but the book shows the answer as 3 x 3 = 9. I haven't mis-read the question, so what have I not understood?

[jackthehat]

You cubed it....

[jackthehat]

I mean that you squared 9.

3 is the square root of 9, therefore if you square 3 you get 9.

[Prudie]

I'm with you clarion. The square root of a number is 3 so the number is 9. the square of the number is therefore 81. Was that the exact wording?

[gingejbee]

I'm with you, Clarion...the number is 9, The square of that number is 81. I suspect a badly-worded (ie ambiguous) question.

[-Talbot-]

Check the book for the wording. As it is worded I agree with you.

[aurion]

I think you're right, as the question is worded.

If you substitute a letter for the unknown number the question reads:
√X = 3 What is X²?

From the first equation, X = 9 and 9² = 81.

[jackthehat]

Set out like that.....you are quite correct.

[Old_Geezer]

You changed the question.
The number is 9
The square root of that number is 3
The square of that number is 81

However maybe the second question was what is the square of the answer/number you have just given; in order to ensure the pupil knows it goes the other way and ends up at the number you first thought of.

[murraymints]

just badly worded...

[murraymints]

as it is presented I would say 81 too.....

[Jackdaw33]

I agree. Very badly worded. It should simply have read: What is the (original) number?

FAO Jack the hat, the cube of 3 is 27, not 81.

[Peter Pedant]

I agree the question is 'wrong'

I think it would be useful as an entry on ambiguity in life
( rather than this is what comes from an English teacher reaching maff)

It is a bit early for this - but in O and A level texts apparently there are deliberate mistakes ( one or two) to prevent plagiarism
( actually detect or confirm plagiarism)

oddly as I ramble to avoid the racist threads
in accounts last night - we had: " blah blah from the capital account. Expenses were paid from that account...."
and the candidate was expected to realise that expenses CAN'T be paid from a capital account so it has to be another account referred to.... " and we all went like: do the question setters speak English ?
[ we also get double negatives and implied double negatives]

[Peter Pedant]

I think it would be useful as an entry on ambiguity in life

sorry that should be

I think it would be useful as an entry to a discussion with your daughter on ambiguity in life and how ambiguity will always be there.

[sozza automatic blue line of deletion occurring]

[Jackdaw33]

It took me a while to get used to the idea that in French and Russian (and perhaps in other languages with which I am not familiar) double negatives are an essential part of the language. I ain't going nowhere makes perfect sense to a Russian, I ain't going anywhere would leave him bewildered.

[Old_Geezer]

Can they not think logically ?