Year 4 Maths should it be this hard?!

[Shufflebum]

Struggling with this homework question
Find the missing number.
Each box holds a 2 digit number
The first number is 10 more than the second
The second number is 10 more than the third

+ +__ = 87

Thank you

[MsMommie]

It looks pretty standard year 4 math to me OP

[Whitelisbon]

39, 29, 19.
Call number 3 x.
Number 2 is x+10
number 1 is x+10+10
so, x+x+x+10+10+10=87
3x=87-30=57
x=19

[ClashCityRocker]

Seems hard for Y4 to me.... I got as far as the numbers would have to end in 9 to get the 7 at the end and then probably would have trialled and errored it till it fit..

[Shufflebum]

Sorry forgot to check back, thanks for the replies I can kind of get it but still think it's hard for an 8year old (and a 37 year old!)

[steppemum]

whites method may be correct, but they would not expect a year 4 to do that algebra, it is not normal year 4 level.

I suspect that they intend you to do it by trial and error.

so, if each one is 10 bigger than one before, each ends in same number:
so start with a guess
could be 27, 37, 47 - Oh no that is much too big. Start lower

17, 27, 37 = 81 Oh that is nearly there, but it is 6 too small.

Then a big of mathmatical thinking to see you need to spread the 6 over the three numbers, so they each get 2 more

which gives you 19, 29, 39

So, it does require thinking, but not unreasonable for year 4

[OutwiththeOutCrowd]

Another possible way to look at it is to divide 87 by 3 giving 87 as a sum of 3 equal parts:

87 = 29 + 29 + 29

Then to fulfil the criteria given, take 10 away from the third number and add to the first:

87 = 39 + 29 + 19

[steppemum]

Oh nice method Outwith

(much more properly mathematical than mine )

[OutwiththeOutCrowd]

Not at all Steppe! I thought what you had to say made a lot of sense - judicious trial and error is a good technique. My DS is in secondary now - and they still use it in maths for some problems.

[steppemum]

@shufflebum

thought you might like to come and see other ways of looking at it, in case you get more the same?

[Shufflebum]

Appreciate all the responses, thank you. The last two are more my way of thinking and to my mind simpler for an 8 year old (and a 37 year old )

[Fadingmemory]

Take away the “extra” which totals 30. Thus, 87 - 30 = 57. 57 divided by 3 = 19.

So first number is 19, second is 29, third is 39. 19 + 29 + 39 = 87. HRTWT so sorry if that’s been suggested x times already. I am no mathematician - was not allowed to take ‘O’ Level.

[TeenTimesTwo]

y4 I would expect trial and error.

[eddiemairswife]

This is the kind of problem I would have been doing at my 1950s Grammar School.

[IdahoJones]

Looking back , OP, (I'm older than you!) I'd probably have had that maths for Year 6 and the 11+ exam.

However, we were expected to progress much more rapidly in secondary and DS assures me my maths O level paper - which I've kept - was his A level standard last year.

But 'progress or fail' wasn't sustainable in British (?English) education so other methods and ideologies crept in. Many of these 'new methodologies' have failed themselves, though, not least because the pedagogy isn't good enough during class time - itself down to issues such as larger class sizes, mismatches between teachers' training and the dreaded worksheets, and other factors.

I do a little bit of tutoring occasionally for pupils with additional needs and finding that 'sweet spot' where they understand the explanation is an intensive 1:1 process. Fruit is sometimes involved

[JustRichmal]

I should think the child can do this by now, given they have had a year to practise.

[sherbsy]

Looks spot on to me and what my Year 4 DS gets. It's not easy but then it's not supposed to be with all the reasoning and problem solving that's been plonked into the curriculum.

I got these Year 4 Maths books for him a while ago and a little practise every now and then helped him understand that the answer isn't always on the right side of the equals symbol!!!