Answer:
Feed me and I live. Give me water and I die. What am I?
I start new then become old. Start clean but become dirty. I usually start big then become little. What am I?
My teeth help me suck.
I am an odd number. Take away a letter and I become even. What number am I?
I am pronounced as one letter written with three. I come in blue black brown or grey. Reverse me and I read the same either way.
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.