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

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

One day, John and his friends were playing around. Jacob hit something with a Pin and it popped. John's dad came into the room that very moment, but he wasn't mad. In fact, he was smiling. What did Jacob hit?

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?

I know there are two methods by using three time the same number with a plus(+) operator , you can make sum as 60.

One of them is 20+20+20.

whats the other way ?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

O_er_t_o_

Complete the missing letters of the given word.

I am under you when I am whole.
I shift above you if you remove the first letter.
I come all around you if you remove the second as well.

Can you tell me who I am?

Do You See It?

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