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?

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

Replace the question mark with the correct number.

No matter how little or how much you use me, you change me every month. What am I?

Here is a mathematical expression that also secretly tells a movie name. What movie is that?

What can go up a chimney down, but can’t go down a chimney up?

Find the number of squares in the below picture

Yesterday I fell from 30 feet high ladder but I don't get hurt. Why?

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?