I’m tall when I’m young, and I’m short when I’m old. What am I?

An infinite number of mathematicians are standing behind a bar. The first asks the barman for half a pint of beer, the second for a quarter pint, the third an eighth, and so on. How many pints of beer will the barman need to fulfill all mathematicians' wishes?

What is the value of 1/2 of 2/3 of 3/4 of 4/5 of 5/6 of 6/7 of 7/8 of 8/9 of 9/10 of 1000?

Make eight squares by moving only two matchsticks.
Note- Square can be of different sizes.

You need to move three matchsticks to form three squares. Can you do it?

Can you find out the number that should replace the question mark with a valid reason?

A man fell off a smuggling boat into deep water. He could not swim and he was not wearing anything to keep him afloat. It took 30 minutes for the people on the boat to realize someone was missing. The missing man was rescued two hours later on the return trip. Why didn't he drown? Note:- He didn't know swimming, the sea was deep, and He wasn't holding anything

You measure my life in hours
I serve you by expiring
I vanish faster when I am thin
and slower when I am thick
The wind is my energy
What am I?

Things are just as they seem, right? Well, check again.
Can you count the number of tigers in this picture ?

If you drop me I’m sure to crack, but give me a smile and I’ll always smile back. What am I?