Khan/khan-exercises — Issue #5150: Properties of numbers 1 - what number could replace v below
Author: KhanBugz
Created: 2011-10-28 21:15:46+00:00
State: open
Labels: chrome, vista

Reporter: michelle_sturm@yahoo.com

the first question in this area is not explained in any way by all three videos.
How does (9+6)+5=9+(v+5)
All three videos only show what is done with parenthesis removed but they do not give an example of a similar problem as the one I showed above. I still do not understand how adding three numbers gives you nine.

[properties_of_numbers_1.html?seed=173&problem=associative-show-left](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/properties_of_numbers_1.html?seed=173&problem=associative-show-left&debug)

["4"]

Mozilla/5.0 (Windows NT 6.0) AppleWebKit/535.2 (KHTML, like Gecko) Chrome/15.0.874.106 Safari/535.2

MathJax is loaded, ready, queue length: 0