310 likes | 432 Views
Generalising from number properties to algebra. A Adviser in Numeracy, Mathematics and NCEA. Teaching progression (adapted from Pierre – Kieren). Materials. Images. Knowledge. A Teaching Progression. Start by: Using materials, diagrams to illustrate and solve the problem Progress to:
E N D
Generalising from number properties to algebra A Adviser in Numeracy, Mathematics and NCEA
Teaching progression (adapted from Pierre – Kieren) • Materials Images Knowledge
A Teaching Progression Start by: • Using materials, diagrams to illustrate and solve the problem Progress to: • Developing mental images to help solve the problem Extend to: • Working abstractly with the number property
To reinforce and consolidate Move back and forth between: • Using materials, diagrams to illustrate and solve the problem and: • Developing mental images to help solve the problem and: • Working abstractly with the number property
Discovering algebraic ‘rules’ for expanding Based on an array model for multiplication • Ideas adapted from • Cyril Quinlan. Analysing teaching/learning strategies for algebra. P 459-464. MERGA 18 (Eighteenth annual conference of the mathematics education research group of Australasia Darwin 1995). • http://www.blackdouglas.com.au
One bracket with addition • Start with 3 rows of 7 counters
Discuss how this might be written Focus on
Place a straw between two columns What does it now show?Record it as
How else can you place the straw to show the same thing? Discuss what this shows:
How else can you place the straw to show something different?
How many different ways of placing the straw can you find? • How many different ways can you find of writing ? • Record them all. • Can you find a pattern?
Repeat using different numbers with one straw. • Progress to using grids to show the same thing.
A suggested progression • Start with rows of counters in columns • Use a straw to generate different number properties • Repeat for different numbers • Generalise number properties with words • Extend from counters to grids or arrays • Generalise properties using symbols
Investigate • Two brackets with addition • One bracket with subtraction • Two brackets with subtraction
Is the use of counters necessary? Do students need to cut out grids or is shading of rectangles sufficient? How important is recording? What is the best way of leading into the use of symbols? Questions to consider…