Using the clues below, what four numbers am I thinking of?

The sum of all the numbers is 31.
One number is odd.
The highest number minus the lowest number is 7.
If you subtract the middle two numbers, it equals two.
There are no duplicate numbers.

An artist while painting a scenic beauty, decides to paint three layers of blue colour on the sky.

Which layer will go on the first?

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

A man was just doing his job when his suit was torn. Why did he die three minutes later?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

What you cannot hold but it is yours?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?

There once were seven dwarfs who were all brothers. They were all born two years apart. The youngest dwarf is seven years old. How old is his oldest brother?

What does this simple rebus mean?