Prove that the below maths equation is true.

8 + 8 = 91

A boy was locked in a room by some robbers. All that is in the room is a piano, a calendar, and a bed. The room is locked from the outside. What does he eat, drink, and how does he escape and get out?

Prove that twice of ten is the same as twice of eleven.

What is the centre of gravity?

I am a type of room you cannot enter or leave. Raised from the ground below, I could be poisonous or a delicious treat. What am I?

How is the moon similar to a dollar?

How far can you walk into the woods?

It's a 7-letter word.
If we remove 1 letter from it, it remains the same.
If we remove 2 letters from it, it remains the same.
If we remove 3 letters from it, it remains the same.
If we remove all the letters from it, still it remains the same.
What is it?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

What is both possible and impossible at the same time?