Can you replace the question mark with the correct letter?

6 + 6 + 6 = N
7 + 7 + 7 = E
8 + 8 + 8 = R
0 + 0 + 0 = ?

You are given a cube that is made with the help of 10x10x10 smaller cubes summing up to a total of 1000 smaller cubes. You are asked to take off one layer of the cubes.
How many remain now?

what's the probability of getting a king or a queen from a pack of 52 cards?

Can you solve the tricky chess rebus puzzle below by ciphering the hidden meaning?

If we add four times the age of John four years from now to five times his age five years from now we get ten times his current age.

How old will John be two years from now?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

You enter your friend's room. He is not in his room. Although you see that on the bed there are two dogs, five cats, two giraffes and three pigs. Also, a couple of chickens and ducks are flying in the room.

Calculate the number of legs standing on the floor.

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?

Find the next number in the series.
1 10 24 43 67 ?

What do you think with the below Picture ?