Which number should replace the question mark?

The below mentioned letters have been placed in a order using a logic.

DEAD, BALL, FEAR, SHOP

Can you find the logic?

How many Watermelons are there in the below picture?

How many letters are in the alphabet?

When you stop to look, you can always see me. But if you try to touch me, you can never feel me. Although you walk towards me, I remain the same distance from you. What am I?

Spot 5 differences in two Christmas tree below:

What is always in front of you but can’t be seen?

I organized a small get together at my home.
In the party , i have a barrel with some whiskey in it.

Suddenly Guest 1 say 'I bet this barrel of whiskey is more than half full'.
'No, it's less than half full' Guest 2 replied.

I don't have any measuring instrument and without removing whiskey from it , how can i determine which of the guest is right ?

What kind of tree can you carry in your hand?

Replace the question mark with the number below given a simple math problem.