How many times can you subtract the number two from the number fifty?

The more you take me, the more you leave me behind.
Who Am I?

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

Explain?

What breaks yet never falls, and what falls yet never breaks?

I am a normal creature, but I have five hands. I can even have more but even then I will be considered normal.

Who am I?

I hide my treasure in the ground, my tail is big and fluffy. If you spot me in a tree, please don’t call me scruffy. What am I?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

What demands an answer, but asks no questions

In four steps you need to move the word 'cold' From 'warm' by replacing one alphabet at a time such that every word formed at each step is acceptable in English Dictionary.

Why 1729 is a magic number? Answer Logically.