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

As easy as you can get into me, it is as hard to get out of me.

Do you know what I am?

When Jack was six years old he hammered a nail into his favourite tree to mark his height. Ten years later at age sixteen, Jack returned to see how much higher the nail was. If the tree grew by five centimetres each year, how much higher would the nail be?

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

There was a competition where the contestants had to hold something. At the end of the event, the winner was a person who had no hands or feet. What was it that the contestants had to hold?

If in a car race, the man who came two places in front of the last man finished one ahead of the man who came fifth, how many contestants were there?

Using eight eights and addition only, can you make 1000?