What Am I Riddles

Question: I am a digit, but two of the ten.
Two of me make a promise.

What am I?

Question: What goes on four legs in the morning, on two legs at noon, and on three legs in the evening?

Question: I am a small room,
but no life lives inside,
no matter what weather looms,
very cold my residents reside.
What am I?

Question: You throw away the outside, eat the inside, and throw away the inside.

Question: A thousand wheels, but move I do not.
Call me what I am, call me a lot.

What am I?