I have teeth but i don't bite. Who Am I ?

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

I am the black child of a white father, a wingless bird, flying even to the clouds of heaven. I give birth to tears of mourning in pupils that meet me, even though there is no cause for grief, and at once on my birth, I am dissolved into air. What am I?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

What runs around the whole yard without moving?

I taste better than I can smell. Who am I?

A bus driver was heading down a street in Mexico. He went right past a stop sign without stopping, he turned left where there was a "no left turn" sign, and he went the wrong way on a one-way street. Then he went on the left side of the road past a cop car. Still - he didn't break any traffic laws. Why not?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

I know a ten-letter word in the English language which can be typed using only the top rows of the computer keyboard.

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?