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

2, 3, 5, 9, 17, _ What is the next number in the sequence?

Can you tell a 3D object that has just two surfaces?

What word is pronounced the same if you take away four of its five letters?

People put me on the table and cut me but do not eat me. What am I?

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?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

A newspaper is supposed to have 60 pages, but pages 24 and 41 are missing.
Which other pages won't be there?

A non-stop marathon is the shared favourite sport of three brothers.

*The oldest one is fat and short and trudges slowly on.
*The middle brother's tall and slim and keeps a steady pace.
*The youngest runs just like the wind, speeding through the race.

"He is young in years, we let him run!" the other two brothers explained, "'because though he is surely number one, he is second, in a way." Why is it?

Andrew sees a very rare bird named "Ruppell's vulture". Soon Andrew was dead. Can you explain the mystery, Mr. Sherlock?