Which alphabet letter is a question?

Can you make four (4) nines (9) equal 100?

I am quite hot but become too cold if you remove the first two letters. What am I?

Count the number of triangles in the below picture?

If in a code language, DISTANCE is written as IDTUBECN and DOCUMENT is written as ODDVNTNE, the how will THURSDAY be coded as in the same language?

I can be cracked, made, told, and played. What am I?

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?

If six children and two dogs were under an umbrella, how come none of them got wet?

The dirtier I get, the whiter I look. Who am I?

What has one eye, but can’t see?