From the "Annenberg Learner Teacher Resources and Professional Development Across the Curriculum:"

Quote
Compare problems involve a comparison of two distinct, unconnected sets. Like the part-part-whole problems, compare problems do not involve action. A relationship of difference, more than or less than is found in compare problems.

Example problem:
Ahmed has two brothers. Christine has three brothers. Christine has how many more brothers than Ahmed?

Example Answers:
3-2=1
or
2+1=3

Apparently, my DS not only understands this concept but he seems to have a better understanding than some adults. Because, so far, it's adults ()one being his own teacher and her team) who can not seem to wrap their head around why "2+1=3" is a perfectly good answer for "Example problem: Ahmed has two brothers. Christine has three brothers. Christine has how many more brothers than Ahmed?" Despite the fact that it is clearly laid out as such in every single internet resource that I have looked at (I am only linking two but I looked at several more!) addressing the issue! smile

Last edited by Irena; 09/26/13 03:43 PM.