Can you replace the question mark with the correct number?

Use the numbers 2, 3, 4 and 5 and the symbols + and = to make a true equation. Conditions: Each must be used exactly once and no other numbers or symbols can be used.

Only one colour, but not one size,
Stuck at the bottom, yet easily flies.
Present in sun, but not in rain,
Doing no harm, and feeling no pain.
What is it?

What type of tree can I carry in my hand?

Identify Me

Hint1: I am a god
Hint 2: I am a planet
Hint 3: measurer of heat

As a whole I am both
safe and secure.

Behead me and I become
a place of meeting.

Behead me again and I am
the partner of ready.

Restore me, and I become
the domain of beasts.

What am I?

The product of three consecutive numbers is 7980.
Then the sum of these consecutive numbers would be?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

How can a man go eight days without sleep?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?