Eight of us go fourth, not back, to protect our king from an attack. What are we?

You bought me for dinner but never eat me. What am I?

If you say my name, I will no longer exist. What am I?

In the figure that has been attached to this question, each digit represents a digit. The similar letters carry the same integer value. Can you expose the original digits?

Can you decipher the two rows to find the hidden word?

Can you find the mistake in the below statement?

Something Extraordinary happened on May 6th 19778 at 12:34am what was that?

Make eight squares by moving only two matchsticks.
Note- Square can be of different sizes.

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.

John was working on a Chemical Mixture whose weight comprise 90% liquid and 10% solid. The total weight of the mixture is 20 pounds. After a while, John noticed that some of the liquid evaporated and now the liquid comprises just 50% of the weight.

What is the weight of the chemical mixture now?