What brings you down but never up?

What do you think with the below Picture ?

John left on a horse on Thursday , was gone for two days, and came back on Thursday after completing his work. How did that happen?

What's a single-digit number with no value?

I have one of the three numbers: 1, 2, or 3 in my mind. I speak only truth. You can ask me just one question for which I will only reply in yes or no or don't know. What question will you ask from me so that you are able to know the number?

In the given picture, you can find two letters missing. When two particular letters are placed in the missing spots, you get an eight-letter word while reading in the anti-clockwise direction. Can you find out the missing letters and the missing word eventually?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

It is a six-letter word.
The first four letters are me.
The second and last letters are the same.
The fourth second and last letter is payment.

Who is it?

Prove that the below maths equation is true.

8 + 8 = 91

Can you circle exactly four of these numbers such that the total is twelve?

1 6 1
6 1 6
1 6 1
6 1 6