First navigation project was placing Mr potatoes heads pieces in the right places and to make him exactly symmetrical I simply
snapped some of the objects to the center line using
X and rotated the piece. Other pieces I used duplicate special after freezing transformations.
Modify > Freeze Transformations
And then I went to
> 
For the duplicate and snapping the crates I noticed they where in line with the grid so I just duplicated and snapped the boxes along the Grid.
X = Grid snapping
C = edge snapping and you can slide it along the edge or bezier curve curve
V = Vertex Snapping
http://download.autodesk.com/global/docs/maya2014/en_us/index.html?url=files/Edit__Duplicate_Special.htm,topicNumber=d30e54155
For the Card game I did a trick
L.click = single selection
Shift+L.click = Toggle selection
Ctrl+L.click = deselect
First I moved all the cards up and then Ctrl+click to deselect the matching cards to move the selected cards back down. I also noticed the cards have a local axis so I just simply typed 180 on the rotate Z info on the side bar.
I'm pretty sure this is all I have to do for this exercise