I have eight fingers and two thumbs but I do not live. What Am I?

What number does the below three word/phrase identify and why?
1. Deck
2. Year
3. Singing in the Rain

Can you place six X (crosses) in below board without making three in a row in any way ?

What work can one never finish?

John’s parents have three sons: Snap, Crackle, and what’s the name of the third son?

Three people enter a room and have a green or blue hat placed on their heads. They cannot see their own hat but can see the other hats.
The colour of each hat is purely random. They could all be green, blue, or any combination of green and blue.
They need to guess their own hat colour by writing it on a piece of paper, or they can write 'pass'.
They cannot communicate with each other in any way once the game starts. But they can have a strategy meeting before the game.
If at least one of them guesses correctly they win $10,000 each, but if anyone guesses incorrectly they all get nothing.
What is the best strategy?

Your mother’s brother’s only brother-in-law is asleep on your couch. Who is asleep on your couch?

John is a strange liar.

He lies on six days of the week, but on the seventh day, he always tells the truth.

He made the following statements on three successive days:

Day 1: "I lie on Monday and Tuesday."
Day 2: "Today, it"s Thursday, Saturday, or Sunday."
Day 3: "I lie on Wednesday and Friday."

On which day does John tell the truth?

I am white when I am dirty, and black when I am clean. What am I?

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