I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?

I am quite hot but become too cold if you remove the first two letters. What am I?

Consider all the numbers between 1 and 1 million. Among all these numbers, there is something very special about the number 8 and the number 2202. What is it?

You have three orange, two pink and five purple balls in the drawer beside your bed. There is no electricity and the room is entirely dark. How many balls must you take out to ensure at least one ball of each colour at least?

Christina is practising her dance steps along with her friends. In a particular sequence, all of them form a row. At that point, Niharika is standing in the 4th position from either end of the row.
Can you find out how many girls are practising together?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

In a basket of apples,
when counted in twos, there was one extra
when counted in threes, there were two extra when counted in fours, there were three extra
when counted in fives, there were four extra
when counted in sixes, there was five extra.

However, if the apples were counted in sevens, no extra apple was left. Can you calculate the minimum number of apples that were present in the basket?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

What can you see in the middle of March and April that you can never see in any other month?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?