Ok, there is no acceleration, because nothing is moving, so the net force of the entire stack must be 0. For block #1, the weights of #2 & #3 combined is the force downward on it, and the force of the floor on #1 is the normal force of the weight of #'s 1-3? Does each block not have any normal...
The problem is to rank the forces exerted from three blocks on top of each other.
Like so:
[10 kg] #3
[5 kg] #2
[2kg] #1
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Here is my reasoning,
From least force, to most force:
a. Force of block #1 on #3; They don't touch, so net force = 0
b. Force of #3 on #1; same thing...