Language aspects of algebra

1. Beginning algebra • - first encounters with algebraic language • Algebraic notations • - variables, equations, functions • Language aspects of algebra • - in classroom practice and in theories of learning • Language aspects of algebra • - from a semiotic/linguistic perspective Language aspects of algebra Jean-Philippe Drouhard, Desmond Fearnley-Sander Bernadette Barker, Nadine Bednarz, Dave Hewitt, Brenda Menzel, Jarmila Novotná, Mabel Panizza, Cyril Quinlan, Anne Teppo, Maria Trigueros

2. Language aspects of algebra Beginning algebra – first encounters with algebraic language

3. Distinguishing an algebraic activity versus the use of symbols • Symbolisation as a process and not seeing algebra as the formal use of symbols • Taking account of the influence of students’ previous or simultaneous experience in mathematics and/or in other subjects (science etc.)

4. Distinguishing an algebraic activity versus the use of symbols Examples of the use of symbols in a non-algebraic activity Geometry: labeling objects and using it e.g. in describing or proving geometrical properties • Symbols with the role of labels:ABC

5. Examples of the use of symbols in a non-algebraic activity Geometry: labeling objects and using it e.g. in describing or proving geometrical properties • Manipulations with symbols but non-algebraic activity

6. Examples of the use of symbols in a non-algebraic activity Geometry: labeling objects and using it • Algebraic activity

7. Petr, David and Jirka play marbles. They have 198 marbles altogether. Petr has 6 times more marbles than David and Jirka has 2 times more marbles than David. How many marbles has each boy got? David ………… d Jirka …………. j ………… 2 times as many as Petr ………….p ………… 6 times as many as 198 : 9 = … Examples of the use of symbols in a non-algebraic activity Solving of word problems: The solution is purely arithmetical but students use letters to record the information described in the assignment.

8. Examples of algebraic activities where formal symbols are not used Problem solvingin natural language (history)

9. Examples of algebraic activities where formal symbols are not used Problem solvingusing non-standard symbols (using and operating on an unknown, using an arbitrary quantity)

10. Symbolisation as a process and not seeing algebra as the formal use of symbols Three levels of the use of language of letters (Hejný, M. et al., 1987): • modelling • standard manipulations • strategic manipulations

11. Modelling • Methodologically the most important level of the language of algebra in relation to the beginning of algebra • Difficulties related to powerfulness of the general standard algebraic language when students are confronted with it too quickly. • !!! Importance of the intermediate notation and verbalisation to maintain the meaning • Example: In the equation 5x + 15y = 280, 5x may be interpreted as: • a certain number of books at $5 each, • Peter has 5times more than Luc, • a certain number repeated 5times, …

12. Modelling • Necessary: longer period of transition from non-symbolic to symbolic records • In this longer period of transition it is important: • to conceive interventions/teaching situations (e.g. the situation of communication – Malara, N. & Navarra, G.; Bednarz, N.) that offer students opportunities for seeing the necessity and the relevance of a symbolisation process. Algebra could appear as a tool of generalisation or modelisation serving to endow symbolism and symbol use with meaning. • to take account of different intermediate notations (particularly those developed by students): fundamental components of the transition to algebraic reasoning and of the construction of meaning for algebraic notations • that student see the pertinence of some conventions (e.g. parantheses)

13. Modelling • Flexibility in using and interpreting different notations at the beginning of algebra • In this longer period of transition it is important: • (Teppo, A.R., p. 581): “For the mathematics students or his or her instructor, whether in high school or tertiary coursework, coming to grips with this type of flexible abstract thinking is an educational challenge that continues to confront all those involved.” • This idea is important not only for high school or tertiary coursework, but also for the beginning of algebra.

14. Modelling • Example:Flexibility in interpreting symbols

15. Modelling B + (B+3) + [(B x 4) + 12] = total amount of articles • Example:Flexibility in using symbols in relation to modelling • (Bednarz, N; p. 75): There are 3 rackets more than balls and 4 times more hockey sticks than rackets. If there are 255 articles in the warehouse, how many balls, rackets and hockeys?

16. Example Taking account of the influence of students’ previous or simultaneous experience in mathematics and/or in other subjects (science etc.) • Conflict with previous conventions used in arithmetic

17. Conflict with previoususe of letters e.g. in geometry - letters seen as labels or unknowns Example (Novotná, J. & Kubínová, M.; p.497) A packing case full of ceramic vases was delivered to a shop. In the case there were 8 boxes, each of the boxes contained 6 smaller boxes with 5 presentation packs in each of the smaller boxes, each presentation pack contained 4 parcels and in each parcel there were v vases. How many vases were there altogether in the packing case? v = 8 x 6 x 5 x 4 (In most school mathematics situations, letters are only used as labels for something that is to be found by calculations. The amount v is taken as an unknown.)

18. Possible conflict with previous or simultaneous use of letters in other fields It seems necessary to have more research in this domain