Wah How to use "Worth"

Worth is used to describe something that has a value equivalent to what is being asked for it either in terms of money or effort. We can use worth in many different ways.

1. To express the quantity of something which is related to its value.
    Can I have $10 worth of gas?
    I would like $5 worth of apples.
    He keeps in the safe $3 million worth of diamonds. 
    (= He keeps in the safe 3 million dollars' worth of diamonds.)
    Martin has 3 million dollars' worth of a car. 
    (= Martin has a car worth $3 million.)

2. To say something that is deserved to do.
    It is worth seeing this movie.
    Your idea is definitely worth thinking about.
    Only a few TV programs are worth watching.
    Don't speak unless you have something worth saying.

3. To say that someone is especially kind or helpful 
    My mother is worth her weight in gold.
    She's worth the world to me.

4. To say something that has a value in money,point, etc.
    This car isn't worth much.
    That ring must be worth a fortune.
    It's worth five points.
    How much is this picture worth?

5. To say something to make somebody feel satisfied, especially when difficulty or effort is involved
    The trip was expensive but it was worth every penny.
    The job involves a lot of hard work but it's worth it.

Note: Worth is used as an Adjective but acts as a Preposition. That's why it's normally followed by a Noun, a Pronoun or a Gerund.

 It is worth climbing this mountain.