You want Bob to have your phone number, but for some reason you can't ask him directly. You have to write Bob a note, and pass it to him through Lucy. Lucy can give you a note back with Bob's reply, but you don't want Lucy to know your phone number herself.
What will you write on the note to Bob?
The word One has 3 letters, in the word three there are 5 letters, in the word five there are four letters and four has four letters in it as well. Whatever number you'll go back to four, and that's why it's the magic number.
I do not breathe, but I run and jump.
I do not eat, but I swim and stretch.
I do not drink, but I sleep and stand.
I do not think, but I grow and play.
I do not see, but you see me every day.
What am I?