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Maths Charity Week Summary

July 7, 2012
Last week saw my school running a Maths charity week with a competition per day. The plan was to keep the entry fee low to maximise participation and try to have competitions that everyone could have a go at.
The competitions were emailed to students and tutors daily and were also displayed on the information screens we have around the school.
The competitions were run in Maths lessons with whichever classes had Maths that day. Students could enter at break or lunch time too if they wished.
Here are the day by day competitions with some notes. We didn’t run one on Friday as we had a collapsed timetable day.

Monday – sweets in the jar

A classic. Estimate how many sweets were in the jar or bottle. You can hold it and/or try to count them but you may not open them. I used a bottle and a jar so that it would be easier to pass them around the classes. With better planning next year, I’ll have two jars the same size.

The bottle estimates were severely under in most cases while the jar guesses were a little better but it was still common to underestimate.



The closest guess for the bottle was 441 (the only guess higher was 500). The closest guess for the jar was 355.
Tuesday – guess the weight of the six pack

I had two packs to make getting round the classes easier. I meant mass but said weight with an asterisk to try and be helpful. The total mass of all six cans, contents and wrapping was required.
Quite a few students had some attempt at working this one out and perhaps it’s not too surprising that it was year 12 students that won this.
In hind sight, I probably won’t do this one next year unless I can get the cans on special offer – they were quite pricey!


There was wild variation in the guesses but the closest was 2100 with the second closest being 2200.

Wednesday – average age of the maths department
A popular competition with lots of entries. I think this was a combination of the fact that students were more aware of the competitions happening, the fact that it was a fairly personal competition and we also didn’t have to pass anything around to be able to have a guess.
As we all know, students are frequently appalling at guessing the ages of adults although I fared quite well with many putting me in my 20s (I’m actually 33).


The correct answer was 40.23077 and the closest guess was a scarily accurate 40.23. There were also two close guesses of 40.2. I shared the prize between these entries.

Thursday – big competition, CDs down the corridor [bigger prize, higher entry price]


Nice and simple – how many CDs would fit down the maths corridor? There was much need for clarification:


  • A single line of CD cases down the corridor (ie not covering the whole area of the floor)
  • Not stacked up on top of each other to the ceiling
  • CD cases laying flat on the floor
  • Orientated so that they would open towards the short ends of the corridor (cases aren’t square)
Anyway, lots of them tried to pace out the corridor, count the tiles or borrowed metre rules (we didn’t let them borrow the trundle wheel). They pretty much all measured the CD case with varying levels of accuracy. The girl who won was pretty accurate with her method and came up with 235.56. My calculations are shown here:

Interestingly, lots of them counted the tiles (110 plus two half tiles) and saw that each tile wa
s about 2 cds. Multiplying gave lots of answers of 220 or 222.
I emailed to show them the following picture and how those ’rounding errors’ mounted up to quite a few more CDs.



So what have we learned? It was certainly lots of fun and fitted well with this awkward time of year (the week before our enrichment/activities week). Mean average and measuring has been reinforced in many students. A lot now know that 1 litre weighs about 1 kg.

We raised £32.20 after taking out the costs and we’ll certainly be looking to build on this next year.



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One Comment
  1. Anonymous permalink

    I’m glad to hear that it was such a success. Well done to you and it’s very interesting to see the results.On a personal note, it’s nice to know that not only was one of my suggestions used, but that it was also a popular competition.It’s amazing to see how accurate some of the guesses/estimations were. It would be interesting to see what the spread of answers for each competition were in form of a graph and also to know the extreme answers from both ends of the spectrum (especially the highest average age suggested).I have some questions and suggestions, which I hope you’ll like:1. Monday’s competition. Were the jar and bottle treated as separate prizes or was the competition to estimate how many sweets there were in total when the two containers were combined?Either way, if you were to do it again, I think it would be a good idea to continue using two different sized containers as otherwise, it’s surely just a case of estimating how much is one of them and multiplying it by two (presuming two containers of the same size and shape would contain roughly the same amount of sweets).Also, if you used two different containers, you could charge separate entries for guessing the amount contained within each, allowing you to give out two prizes for one competition.2. Tuesday’s competition: I think the use of the word mass might have been confusing. You may know more about this than me, but my understanding is that an object’s weight depends on its environment, while its mass does not. I would have thought using weight would have been an easier concept.Also, do you think the choice of beverage might have impacted on the number of entries? Perhaps next year, you could offer a six pack of the winner’s choice or wrap the six pack in wrapping paper to hide it’s flavour (this may of course result in less entries not more, a decision I leave to your judgement).3. Wednesday’s competition: Excellent one. Only change for next year might be using height instead of age, as unless there are major changes in the staffing of the Maths’ Department, the average will not have changed much.4. Thursday’s competition: It’s one of those things that becomes obvious with hindsight, that there would be confusion about the orientation of the CDs, which of course would have a massive impact on the number that would fit. I personally had assumed you meant standing on their edge in single file down the corridor. I didn’t realise you meant laying flat.Perhaps next year one of the photos could have an example of a few CDs laid out? Or perhaps next year you could use maths textbooks?It would be interesting to see a break down of how much was raised by each competition. I assume the the CD competition had the most expensive prize? Was the value of the prize reflected in the number of entries?Do you feel that you could have increased the entry cost? One assumes that even a small increase would have netted a large overall increase in the money raised.Also, what was the charity that the money was raised for? Do you think adding this information to the posters would have helped increase entries?Were the parents informed before the first event on Monday? I wonder how many pupils bring spare money to school on a normal school day.

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