The letter “g”.

The letter “g”.

Fingers.

A password.

A hole.

9.

How much does the bag of potatoes weigh?

Let the weight of bag be x then according to the statement 50/0.5x = x solve this you'll get x=10

Who am I?

A dentist!

How many cats are in a small room if in each of the four corners a cat is sitting, and opposite each cat there sit 3 cats, and at each cat's tail a cat is sitting?

Four cats, each near the tail of a cat in an adjacent corner

Of course it is. A $100 bill is worth more than a $1 bill (newer one).

Lunch and dinner.

Because it would be a foot.

How is this possible?

He is self-employed. He is his own boss.