Good Riddles

Question: What two things can you never eat for breakfast?

Question: You have a cube made of 10 x 10 x 10 smaller cubes, for a total of 1000 smaller cubes. If you take off 1 layer of cubes, how many remain?

Question: You have two buckets: one with only white marbles and one with only black marbles. The two buckets have the same number of marbles.

How can you rearrange the marbles to maximize your chances of grabbing a white marble from each?

Question: I have all of your knowledge but could fit in your hands.

What am I?

Question: I am a digit, but two of the ten.
Two of me make a promise.

What am I?