A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

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

How many sides does a circle have?

Begin with a word, five letters to my name,
Remove the first and last but I am the same
Take out my middle and still, I remain.
What word am I?

What has to be broken before you can use it?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

He digs out tiny caves and stores gold and silver in them. He also built bridges of silver and made crowns of gold. They are the smallest you could imagine. Sooner or later everybody needs his help, yet many people are afraid to let him help them. Who is he?

I have four wings but can't fly.
I express no emotions.
I am found on the exact spot every time you look.
I keep toiling away with a little sound.

Do you know what am I?

How many letters are in the alphabet?