Section 1
Mental Calculation Practice: Some Similarities between Strategies used in Senegal and the UK Elisabeth Gerger
Elisabeth lives in the south of Senegal and works with a non-governmental organisation as coordinator for literacy projects in several Senegalese languages. The felt need of women to learn mathematical skills has led her to research the traditional numeracy practices of a people group in the south of Senegal. Her goal is to offer a numeracy programme for women in their own language.
Research has highlighted the fact that basically all ethnic groups have numerical systems
(Crump 1990) and that the ability to count seems to be “intrinsic to being human” (Ascher 1991:6). Many traditional techniques, embedded in everyday cultural practices and often called “informal mathematics” or “street mathematics” (Nunes, Schliemann and Carraher 1993:3), include the use of concrete objects for arithmetical operations as well as mental calculation techniques. These researchers observed that many of these techniques are similar to those used by Western children. Reed and Lave (1981) emphasise the fact that mental calculation practices are found in all cultures, concluding that unschooled individuals have the capacity to calculate mentally, often with great aptitude. Estimation is a technique that is used widely by people with no formal schooling. Gay and Cole (1967) observed that the Kpelle people in Liberia were much better at estimating the number of stones in a pile than an American control group.
In this article I will describe estimation and
mental calculation skills that I observed whilst participating in two events in Thionck-Essyl, a town in the south of Senegal. I observed estimation skills used in cooking a rice dish as well as mental calculation techniques employed by a market vendor who has never been to school. These examples are given in order to illustrate that some of the mental calculation strategies used in Senegal are very similar to those employed in the United Kingdom (UK), even if the context and the tasks involved might be very different.
Cooking a Meal
I spent a morning with Khady, a 36 year old mother of eight children, cooking a dish called 'etoj ekaama', rice with a sauce of ground peanuts and manioc leaves. She is one of the two wives of her husband in this community where polygamy is common. Khady and her co- wife take turns cooking for their husband, all their children and several other relatives who live with them, each woman cooking for two days in a row. The kitchen is a square house made out
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of dried earth. We sit in the small square porch on little stools while cooking.
Khady tells me that the food has to be ready when the children come back from school, which is around 1pm. The exact time is not too important. Traditional measurement of time is mainly defined by nature, for example, the position of the sun. Around 10am (I check my watch), Khady sends a child to the market to buy ingredients for the sauce. Then she goes with me to a nearby garden to collect a bucket full of manioc leaves. Another child is sent to the pounding machine with them. Khady knows from daily practice what size pot to use for cooking, how much water to use for boiling the rice, how much of each ingredient to put into the sauce: three pots of rice, the ground manioc leaves, which after being pounded only cover the surface of the bucket, as well as a piece of dried fish and a piece of dried sea snail, several packets of peanuts that we grind using pestle and mortar,
stock cubes, hot pepper, salt, shrimp powder etc. She also knows from experience how long the sauce needs to simmer.
Pounding peanuts for the sauce
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