What do you answer even though it never asks you questions?

Can you solve this picture maths equation?

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?

In Greek mythology, the Sphinx sat outside of Thebes and asked this riddle of all travellers who passed by. If the traveller failed to solve the riddle, then the Sphinx killed him/her. And if the traveller answered the riddle correctly, then the Sphinx would destroy herself. The riddle:

What goes on four legs in the morning, on two legs at noon, and on three legs in the evening?

Oedipus solved the riddle, and the Sphinx destroyed herself.

Can you count the number of lines in the below picture?

In the given figure, move three matchsticks so that the resulting figure contains two rectangles.

A Doctor always sneezes before the rain. Doctor sneezes, Will it rain?

Solve the following series:
AZ, GT, MN, __, YB

Replace the 'X' with any mathematical symbol to make the expression equal to 111.

18 X 12 X 2 X 3 = 111

What does a man do only once in his lifetime, but women do once a year after they are 29?