O_er_t_o_

Complete the missing letters of the given word.

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?

How many times can you subtract the number 5 from 25?

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?

A man and a dog were going down the street. The man rode, yet walked. What was the dog’s name?

If eleven plus two equals one, what does nine plus five equal?

Why 1729 is a magic number? Answer Logically.

I am a type of food that is often found in the fridge and can be white in colour. What I am?
Hint 1: I am a dairy product.
Hint 2: You can spread me on the bread.

I get hot but I never sweat,
I cook food but I am not a chef,
I have a door but you can't enter me,
I have a light but I am not a lamp.
Who am I?

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?