If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

When I go in I might cause pain. I cause you to spit and ask you not to swallow. I can fill your hole. What am I?

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

I am dry when I go inside, but wet when I am pulled outside.
The longer I am inside, the stronger I get
When I am completely out, I am wet and I literally sag
Who am I?

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

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

What jumps when it walks and sits when it stands?

How many letters are in the alphabet?

If an electric train is travelling south, then which way is the smoke going?

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?