Can you solve this tricky maths equation problem by replacing it? mark with the correct symbol?

19834 -----: 187
15921 -----: 153
17561 -----: 139
13734 -----: ???

What do you see in the image below

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

What is the coolest letter in the alphabet?

A doctor and a boy were fishing. The boy was the doctor’s son, but the doctor was not the boy’s father. Who was the doctor?

Make eight squares by moving only two matchsticks.
Note- Square can be of different sizes.

What demands an answer, but asks no questions

A bomb exploded in a room full of married couples and no one died. How?

He does not have any heart but still, He manages to live.
If you kill him, you will eventually die but yet you kill him.
He cannot run, who is He?

See the given image carefully. What you have to do is move the blue checkers in the position of the black checkers and vice versa. You are only allowed to move the checker to an adjacent empty space. Do it in the least possible moves.