Our product and our sum always give the same answer. Who are we?

A man was gazing through the window of the 23rd floor of the building. He suddenly opened the window and jumped on the other side of the window. On landing on the floor, there was not a sheer mark of injury on him.

How can that be possible if he did not use any kind of parachute and did not land on a soft surface?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

If six children and two dogs were under an umbrella, how come none of them got wet?

What goes up but never comes down?

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

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

Two friends Smith and Andrew were talking about the bravery of their families. Smith told great stories about his courageous grandfather who fought for Britain in "World War I". Andrew told that his grandfather was so brave that in 1919 just after the war he was honoured with a bravery medal with the words "For our Courageous Soldiers In World War I" embedded into it. Smith knows that his friend is lying. How?

How can you take 2 from 5 and leave 4?