Maths question!

(47 Posts)
RosinaCopper Sun 10-Nov-13 22:37:46

Ds was set the following question:

2700 people attended a local event. To the nearest 100:

What is the smallest number that could've attended?
What is the largest number that could've attended?

Ds was a bit stuck, so me, DH and he discussed it before completing it and handing it in. According to his teacher we are wrong! So, I'm interested to know what you think the answers are, (and if you agree with us, whether to raise it with the teacher?)

itsjustplayingonmymind Sun 10-Nov-13 22:40:22

Smallest 27
Max 30
I may be wrongsmile

lougle Sun 10-Nov-13 22:41:05

2650; 2749

lougle Sun 10-Nov-13 22:42:54

The reason I give those figures is that if you round, then half our more of the rounding figure round up, less than half rounds down.

StarsAboveYou Sun 10-Nov-13 22:43:48

I'm with Lougle

starlight1234 Sun 10-Nov-13 22:43:51

agree with Lougle...

What did teacher say ..what did you say?

usernameunknown Sun 10-Nov-13 22:43:52

Surely both answers are 2700 if you know that's how many attended?

What a stupid question confused

CrocodileScream Sun 10-Nov-13 22:43:54

That sounds nonsensical to me.

RosinaCopper Sun 10-Nov-13 22:44:08

lougle that's what ds had as his answers! Wrong, according to his teacher.

usernameunknown Sun 10-Nov-13 22:44:36

But it doesn't say 'approximately 2700 attended'

usernameunknown Sun 10-Nov-13 22:45:24

So what WAS the answer?

CrocodileScream Sun 10-Nov-13 22:45:47

Ah I see what you mean Lougle but the way it is written it seems like it wanted you to present your answers to the nearest hundred. Badly written question.

I agree with lougle

PiqueABoo Sun 10-Nov-13 22:46:12

Definitely:
2650
2749

RosinaCopper Sun 10-Nov-13 22:50:35

The exercise was about rounding and the teacher marked 2650 as wrong and wrote 100 (we think she made a mistake there!) and marked 2749 as wrong and wrote 2700.

Given that the exercise was about rounding, it seems mad to have both the answers as 2700!

But we also thought that the question was badly worded and perhaps if it has said 'to the nearest 100, 2700 people attended' and then asked for the smallest and largest numbers, we would have been correct.

The thing is, would you raise it with the teacher (it's not long until parents' evening), or let it go this time, but keep an eye on future homework? I don't want ot be a nightmare parent who thinks her little darling is always right, even when they're wrong IYKWIM!

starlight1234 Sun 10-Nov-13 22:55:32

A friend of mine had an issue with a wrong answer in homework book..Dad wrote a comment in book and she agreed with what he had said...

lougle Sun 10-Nov-13 22:58:19

Ah, so she's saying that just one person could have attended, but that would be 100 to the nearest 100. 2700 would be 2700 to the nearest 100.

My fault for turning a stupid question into a logical one wink

RosinaCopper Sun 10-Nov-13 23:05:27

I'm just glad that it's not only us that misunderstood a badly worded question!

PiqueABoo Sun 10-Nov-13 23:07:33

If they missed out "Up to.." or whatever off the front of the question then I think 1 -49 attendees to the nearest 100 is zero. So

0
2700

They probably didn't do that though, so I would explain to child that to err is human and count your blessings that they haven't yet been rated an entire SATs level (not sub-level) too low for maths, as happened to my DD.

steeking Sun 10-Nov-13 23:07:58

I agree it was worded really badly. It should have said "To the nearest 100 people, 2700 attended the event" that's the rounded number.
The miminum attendance that would round to this figure would be 2651 (if its 2650 you round to the even number so that would be rounded to 2600).
The maximum would be 2749 as you stated, 2750 would get rounded to 2800 following the even/odd rule.

steeking Sun 10-Nov-13 23:16:21

Actually if someone could clarify the odd/even thing I would be grateful as I'm starting to doubt that. It is def what Ds's were taught in the last couple of years.
I was taught what lougle said.

RosinaCopper Sun 10-Nov-13 23:21:35

I din't know there was an even/odd rule (it's a very long time since I did 'O' level maths!)
I also thought that 5 was always rounded up, and that with rounding to the nearest 100 you could ignore the units and just consider the tens - we had to explain to ds why the maximum was 2749 and not 2744 which was his first answer as he felt that 749 would be first rounded up to 750 and then up to 800 based on the 'high five' rule that he's been taught.

I'm obviously not as good at maths as I thought!

RosinaCopper Sun 10-Nov-13 23:23:26

Sorry, slow typing and laundry!

I'd like a clarification of the even/odd thing, too, as I was also taught what lougle said which is why our answers were the same!

lougle Sun 10-Nov-13 23:25:54

You can't round twice!

I still don't get why you can't just argue that the answers are both 2700 because they wrote such a shitly worded question.

The teacher should have been on our last maths thread where we were discussing how often wording makes the difference to how how we answer a maths question.

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