Before Mount Everest was discovered, what was the highest mountain in the world?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

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

If eleven plus two equals one, what does nine plus five equal?

Can you write down eight eights so that they add up to one thousand?

How many sides does a circle have?

How many times can you subtract the number 5 from 25?

There are four 3-link chains. All you have to do is join them into a big 12-link chain. For joining two closed links, one of the links must be cut and placed onto the other link for closing.

How many minimum links will you have to cut to make the big chain?

My thunder comes before the lightning; my lightning comes before clouds; my rain dries all the land it touches. What am I?

Samuel was out for a walk when it started to rain. He did not have an umbrella and he wasn't wearing a hat. His clothes were soaked, yet not a single hair on his head got wet. How could this happen?