What does this simple rebus mean?

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

How old is your son? asked a man to his neighbour. My son is five times as old as my daughter and my wife is five times as old as my son. I am twice as old as my wife whereas my grandmother, who is celebrating her eighty-first birthday is as old as all of us put together.

How old is the man's son ?

Transform the word THINK into BRAIN while changing only one letter at a time in a manner that each of the word in the process is a real word!!!

What does this rebus riddle means ?

What do you get if you add 2 to 100 four times?

There are two words one resembles the "state of rest" and the other is related to "writing/reading material".

Can you name these two words which also sound similar?

What goes through cities and fields, but never moves?

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

If two's company, and three's a crowd, then whats four and five ?