Maths question for an 8 year old
Discussion
Firstly, I wasn’t sure which sub forum to put this under so apologies if this is the wrong place.
Anyway, my 8 year old has been set some school work and, as the designated temporary home schooling teacher in our household, it’s for me to explain and assist.
The question is ‘Ben has 5 coins in his pocket. How much money might he have? Now, on the face of it I can’t imagine an 8 year old is actually expected to work out all the variations, although the follow on questions suggest otherwise.
Not being to the level of a year 3 maths student, I’m struggling to work out, if only out of curiosity, the total number of monetary variations. Can anyone assist? Presumably this is easier than it looks?
Thanks (from a slightly embarrassed dad)
Anyway, my 8 year old has been set some school work and, as the designated temporary home schooling teacher in our household, it’s for me to explain and assist.
The question is ‘Ben has 5 coins in his pocket. How much money might he have? Now, on the face of it I can’t imagine an 8 year old is actually expected to work out all the variations, although the follow on questions suggest otherwise.
Not being to the level of a year 3 maths student, I’m struggling to work out, if only out of curiosity, the total number of monetary variations. Can anyone assist? Presumably this is easier than it looks?
Thanks (from a slightly embarrassed dad)
Heathwood said:
CharlesElliott said:
Maybe it is expecting just 1 (or 2) answers?
You’d have thought so, however follow on questions discuss methodology to ensure all variations are accounted for and that there are no repetitions. CubanPete said:
Surely that isn't 8 yr old level Maths?Gary29 said:
I hope not!
Is this another case of not getting the full and exact original question correct?
Yes I'd say we need to see the full unedited question.Is this another case of not getting the full and exact original question correct?
edit :- I'd say the answer is as above 5p to £10.
But if the question is "how much might he have" then £9 is a correct answer
Heathwood said:
Not that straightforward I fear.
The follow on questions/comments are:
- how will you ensure you find all the variations?
- how will you ensure you don’t repeat any totals?
- perhaps start with just 2 coins first to develop your system
Hmm
The follow on questions look to me more about making the students think about methodology, rather than formulae or working out how many variations there are .The follow on questions/comments are:
- how will you ensure you find all the variations?
- how will you ensure you don’t repeat any totals?
- perhaps start with just 2 coins first to develop your system
Hmm
How will you find all the variations? Take the suggestion of starting with two coins in the pocket as the start point for the methodology. Say the first coin is a 1p. The second could be any of the 8 coins, so you have 8 possible 1p-based combinations (1+1, 1+2. 1+5, etc).
Now take the 2p as your first coin. You still have 8 possible combinations that are 2p-based, but you already have the 2+1 combo as 1+2 in the first stage above. So when you start with the 2p, the second coin could be any of seven of the remaining coin types: 2 to 200.
Now take the 5p as your first coin. Again, 8 possible 5p-based combinations, but you have 5+1 and 5+2 already ticked off at stages 1 and 2 above. So now the second coin can be any of the six remaining coin types.
At this point you can see a pattern emerging, and the trick is to formulate a rule that describes what's going on.
Then try again with a three coin pick.
It looks like this is intended to be a collaborative group activity, so not really ideal for remote home learning: https://nrich.maths.org/142/note
CubanPete said:
Of course this ignores that £5 coins are legal tenderhttps://en.wikipedia.org/wiki/Five_pounds_(British...
Dixy said:
CubanPete said:
Of course this ignores that £5 coins are legal tenderhttps://en.wikipedia.org/wiki/Five_pounds_(British...
BlackTails said:
The follow on questions look to me more about making the students think about methodology, rather than formulae or working out how many variations there are .
How will you find all the variations? Take the suggestion of starting with two coins in the pocket as the start point for the methodology. Say the first coin is a 1p. The second could be any of the 8 coins, so you have 8 possible 1p-based combinations (1+1, 1+2. 1+5, etc).
Now take the 2p as your first coin. You still have 8 possible combinations that are 2p-based, but you already have the 2+1 combo as 1+2 in the first stage above. So when you start with the 2p, the second coin could be any of seven of the remaining coin types: 2 to 200.
Now take the 5p as your first coin. Again, 8 possible 5p-based combinations, but you have 5+1 and 5+2 already ticked off at stages 1 and 2 above. So now the second coin can be any of the six remaining coin types.
At this point you can see a pattern emerging, and the trick is to formulate a rule that describes what's going on.
Then try again with a three coin pick.
It looks like this is intended to be a collaborative group activity, so not really ideal for remote home learning: https://nrich.maths.org/142/note
Thanks BlackTails, this is pretty much what we’ve done. Essentially, demonstrating a recognition of a pattern / methodology and acknowledging the extent to which this would continue. How will you find all the variations? Take the suggestion of starting with two coins in the pocket as the start point for the methodology. Say the first coin is a 1p. The second could be any of the 8 coins, so you have 8 possible 1p-based combinations (1+1, 1+2. 1+5, etc).
Now take the 2p as your first coin. You still have 8 possible combinations that are 2p-based, but you already have the 2+1 combo as 1+2 in the first stage above. So when you start with the 2p, the second coin could be any of seven of the remaining coin types: 2 to 200.
Now take the 5p as your first coin. Again, 8 possible 5p-based combinations, but you have 5+1 and 5+2 already ticked off at stages 1 and 2 above. So now the second coin can be any of the six remaining coin types.
At this point you can see a pattern emerging, and the trick is to formulate a rule that describes what's going on.
Then try again with a three coin pick.
It looks like this is intended to be a collaborative group activity, so not really ideal for remote home learning: https://nrich.maths.org/142/note
I think the question will attract a very wide spread of responses to varying complexities. I suspect the teachers will just be interested to see what the kids do when given such a task.
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