give an example of sets X and Y such that X cross Y not equal Y cross X
give sets such that Xcross(YcrossZ) not equal (XcrossY)crossZ
probably too late
take your pic! any once X and Y are different sets (both non-zero) the cross-product would not commute. make X and Y different sizes to make sure.
again, pick pretty much any different sets for X, Y and Z. the chances of you getting one that doesn't work here are slimgive sets such that Xcross(YcrossZ) not equal (XcrossY)crossZ
probably too late