# A nose for maths

14th March 1997 at 00:00
There is an old saying, "Red nose at night children's delight, red nose in the morning, teacher's warning". As children look forward to this evening's comedy extravaganza on television, teachers will be contemplating the earlier part of the day. One solution to red nose day (other than grin and wear it) is to see it for what it is - a great mathematical opportunity.

At first glance this year's noses may seem less usable as maths equipment than those supplied in the past. Yet covering the noses with fur has increased the mathematical potential, if not the comfort. The first problem children might wish to consider is how to cover a red nose with fur. Looking at various ball-shaped soft toys or at tennis balls may suggest possibilities. Just as children can discover the net of a cuboid or other shape by cutting open a box, a red nose can be peeled to reveal the shape of its wrapping. The resulting six-petal shape is quite interesting and provokes more questions. How many lines of symmetry does the shape have? What is its approximate area? How were the nose covers cut from a large sheet of fur with minimal waste?

Once peeled the nose is like past noses, only not red. Its transparency, and its halfway line are advantages if you are interested in the distance round or across it, or its volume. Children may be surprised to find where the water level comes if the nose is one quarter full. This can be illustrated by studying the balls provided to measure washing liquid and seeing how the distance between markings varies.

Finally the noses can be filled. How heavy do the children think they can make them? How much will they be worth when filled with coins? This year's noses also come with a plastic bag inside for collecting loose change so similar questions can be asked about this. Can the children estimate how many 2p coins the bag would hold and how long a line they would make? The information on the money bags repays attention, too. We are told, for example, that #163;82 million worth of 2p pieces are in circulation. You can't help wondering how many 2p pieces that is, and the question "How did you work it out?" is not far behind.

One of the day's strengths is that we are bombarded with statistics as well as slapstick comedy. Did you know, for example that last red nose day 98 per cent of the population knew that it was happening? I suspect the 2 per cent were not teachers. Almost all the fundraising literature carries the sort of figures that beg you to start calculating. We are told that Wall's donate 10 per cent of the price of each Big Nose Lolly to Comic Relief. Someone in your class will know what a lolly costs - let's hope it's a multiple of 10p. In the red nose recipe collection we are exhorted to make at least 100 mini-muffins. Unfortunately, the recipe is for 24 muffins.

Another aspect of red nose day is sponsorship. Suggestions given include eating as many Brussels sprouts as possible, covering the playground with coins or eating chocolate buttons wearing boxing gloves. All lead very neatly to estimation and calculation, though the sprouts might lead to more than that. Another idea is to fill your Wellingtons with custard, walk around in them, then eat the custard. It dawned on me that it was actually designed to evoke a discussion of capacity (of the Wellington), volume (of the foot and a bit of leg), and the difference between the two (in this case the custard)! Try this activity today and your pupils will probably never confuse volume and capacity again.

Even the slogans are mathematical. Thus, advice on running a "red news day" campaign says that to get a message across you must be "clear, convincing, creative and cuddly". All teachers know that two if not three of these are essential when introducing mathematical ideas though we may balk at the fourth. A widely used slogan, designed to get us to part with cash is "small change, big difference". There are mathematical situations where a small change might make a big difference, such as an algebraic expression modified by the moving of brackets, or the omission of a minus sign.

Comic Relief's work continues after red nose day and considering the work done with the money raised might be a viable project. There are materials available to help teachers here, including an excellent video and supporting pack known as "Teacher Relief". To appreciate fully the information given, children will need a feel for the figures and units used. A good example is the part of the work seeking to help families in Africa who must carry all their water from a well. Do the children know how heavy two litres or ten litres of water is and what it means to carry it for a mile?

So go on, enjoy the day. The secret is to see the antics as an estimation exercise and the noses themselves as spheres (only PE teachers say balls). If your vision of mental mathematics is conducting a tables test while sporting a red nose and standing in boots full of custard, then today could be your day.

Jenny Houssart is a lecturer in mathematics education at Nene College, Northampton

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