What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

Can you tell a 3D object that has just two surfaces?

A boy and his father are caught in a traffic accident, and the father dies. Immediately the boy is rushed to a hospital, suffering from injuries. But the attending surgeon at the hospital, upon seeing the boy, says 'I cannot operate. This boy is my son.' How is this situation explained?

I am something people love or hate. I change peoples appearances and thoughts. If a person takes care of them self I will go up even higher. To some people I will fool them. To others I am a mystery. Some people might want to try and hide me but I will show. No matter how hard people try I will Never go down. What am I?

Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

The centre of the third figure is empty. What digit should fit inside?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

One day, John and his friends were playing around. Jacob hit something with a Pin and it popped. John's dad came into the room that very moment, but he wasn't mad. In fact, he was smiling. What did Jacob hit?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

Create a number using only the digits 4,4,3,3,2,2,1 and 1. So i can only be eight digits. You have to make sure the ones are separated by one digit, the twos are separated by two digits the threes are separated with three digits and the fours are separated by four digits