harpazo
Full Member
- Joined
- Jan 31, 2013
- Messages
- 891
Er.. well... I mean, it's not wrong to do this, but I'd be seriously alarmed to see this approach seriously being advocated. I can't even see any applicable lessons to be learned from this that could be generalized to other situations.
I went through school years ago, well before the advent of "Common Core," but what I've seen the lesson plans usually consist of teaching numerical literacy, pattern recognition, and just generally encouraging students to become more comfortable working with numbers. Typically, this is accomplished by teaching the student to see when a number is close to 5 or 10 or how to "pull out" a multiple of 5 or 10 (i.e. 13 = 10 + 3 or 27 = 10 + 10 + 5 + 2).
With reference to this specific example, a much more practical method would be to recognize that 4 = 5 - 1, such that 4 + 5 = (5 - 1) + 5 = (5 + 5) - 1 = 10 - 1 = 9.
This question was given to my nephew on the final exam for his fifth grade class at the end of this year NOT LAST YEAR. He starts 6th grade next week. This is not my question.