Puzzled to the Tenth Degree

[physicsss]

A 10.0 kg box is placed on top of a 40.0 kg box, which rests on a table.


Determine the normal force that the table exerts on the 40.0 kg box.
Is it 10.0*9.8+40.0*9.8?

Determine the normal force that the 40.0 kg box exerts on the 10 kg box.
Is it 10*9.8?

[recon]

Yes, you're right. The normal force is equal to the force exerted in the direction opposite to the normal force (in this case the box or boxes).