Khan/khan-exercises — Issue #6030: Properties of numbers 1 - I don't know the answer 
Author: KhanBugz
Created: 2011-11-11 01:43:19+00:00
State: open
Labels: ie8, ie9, win7

the question looks like this 4+=O+4the "O" is the thing we are tring to replace

[properties_of_numbers_1.html?seed=57&problem=commutative-show-left](http://sandcastle.khanacademy.org/media/castles/Khan:master/exercises/properties_of_numbers_1.html?seed=57&problem=commutative-show-left&debug)

["7"]

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