I don't care where it's from (it could absolutely be from a textbook or workbook provided with the textbook), when people talk about common core math, this is an example of it. Not all public schools are using common core curriculum right now, but if you look into what common core math contains it's a lot of stuff like this.
[–] SpaceLizard 1 point -1 points 0 points (+0|-1) ago (edited ago)
But this isn't even wrong(aside from the typos)... It's called front end estimation. Just because you don't understand it does not mean it should not be taught.
[–] Aaaron 1 point 0 points 1 point (+1|-1) ago (edited ago)
I understand exactly what front-end estimation is, and that's not even correct front-end estimation. That's truncation, and they are very different concepts. I don't see the benefit of teaching kids how to truncate numbers while incorrectly calling it estimation.
EDIT: Quit being such a smug asshole too. Just because you think you understand it doesn't mean it should be taught.