A B C D E

Notes for Session 9, Part A

 Note 2 In this session, we'll be exploring a structural approach to algebra. When we begin to think about properties of operations rather than of numbers, we're moving from arithmetic to algebra, in a structural sense. You may recall that in Session 3 we looked at algorithms through the lens of "doing and undoing." A focus on "what undoes what" often marks the beginning of reasoning about operations. In this session, we'll continue to examine algorithms, as well as other systems that represent a structural approach to algebra. Spend some time thinking through the following exercise. Groups: You may want to put this on an overhead. One hallmark of a move to algebra as structure is a focus on undoing, or inverting, processes; another is comparing them. A simple case of this is the following: Is adding 3 to 2 the same as adding 2 to 3? Is subtracting 3 from 2 the same as subtracting 2 from 3? Thinking about properties rather than individual numbers indicates a move to a structural point of view. Keep this in mind as you work on Problems A1 and A2.

 Session 9: Index | Notes | Solutions | Video

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