How many sides does a circle have?

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

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

During which month do people sleep the least?

Without looking at a calendar, within a minute name, a boy's name using 5 consecutive 1st letters of 5 consecutive months

My first is in chocolate but not in ham. My second is in cake and also in jam. My third at tea time is easily found. Altogether, this is a friend who is often around. What is it?

I have an eye but still cannot see.

Who am I?

I’m orange, I wear a green hat and I sound like a parrot. What am I?

There are five vowels (a, e, i, o, u) in the English language.
Can you tell us a word that contains all these vowels?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?