Introduction to algebra

Algebraic thinking - part 3

Important Teaching Point

Avoid the fruit-salad approach to explaining algebraic statements, for example, referring to 3a + 5b as ‘3 apples and 5 bananas’, or anything that reinforces the ideas that the letters stand for objects or specific numbers.

Then, so many of us have been subjected to explanations in ‘algebra lessons’ that reinforce this misconception that the letters stand for things. For example, it does not help to explain 2a + 3a = 5a by saying ‘2 apples plus 3 apples makes 5 apples’. This again makes us think of a as an abbreviation for apples. What this statement means is: whatever number you choose for a, then ‘a multiplied by 2’ plus ‘a multiplied by 3’ is the same as ‘a multiplied by 5’.