What is so fragile that saying its name breaks it?

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

He loves to dance, twist and prance, he shakes his tail, and as a way he sails, wingless he flies into the sky. What is he?

Find The Missing Number In the Sequence.
6 25 64 ? 32 1

On rolling two dices (six-sided normal dice) together, what is the probability that the first one comes up with a 2 and the second one comes up with a 5?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

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

Can you decipher the below rebus?

PBLUESAISNUERSES

Which of the following words don't belong in the group and why?
CORSET, COSTER, SECTOR, ESCORT, COURTS

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.